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# Assign addresses (co-ordinates) to instructions (landmarks) in a program
# (landscape).
# Use the addresses assigned to:
#   a) replace labels
#   b) add segment headers with addresses and offsets correctly filled in
#
# To build (from the subx/ directory):
#   $ ./subx translate *.subx apps/survey.subx -o apps/survey
#
# The expected input is a stream of bytes with segment headers, comments and
# some interspersed labels.
#   $ cat x
#   == code 0x1
#   l1:
#   aa bb l1/imm8
#   cc dd l2/disp32
#   l2:
#   ee foo/imm32
#   == data 0x10
#   foo:
#     00
#
# The output is the stream of bytes without segment headers or label definitions,
# and with label references replaced with numeric values/displacements.
#
#   $ cat x  |./subx run apps/assort
#   ...ELF header bytes...
#   # ELF header above will specify that code segment begins at this offset
#   aa bb nn  # some computed address
#   cc dd nn nn nn nn  # some computed displacement
#   ee nn nn nn nn  # some computed address
#   # ELF header above will specify that data segment begins at this offset
#   00

== code
#   instruction                     effective address                                                   register    displacement    immediate
# . op          subop               mod             rm32          base        index         scale       r32
# . 1-3 bytes   3 bits              2 bits          3 bits        3 bits      3 bits        2 bits      2 bits      0/1/2/4 bytes   0/1/2/4 bytes

Entry:
    # Heap = new-segment(64KB)
    # . . push args
    68/push  Heap/imm32
    68/push  0x10000/imm32/64KB
    # . . call
    e8/call  new-segment/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # initialize-trace-stream(256KB)
    # . . push args
    68/push  0x40000/imm32/256KB
    # . . call
    e8/call  initialize-trace-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP

    # run tests if necessary, convert stdin if not
    # . prolog
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # initialize heap
    # - if argc > 1 and argv[1] == "test", then return run_tests()
    # . argc > 1
    81          7/subop/compare     1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0/disp8         1/imm32           # compare *EBP
    7e/jump-if-lesser-or-equal  $run-main/disp8
    # . argv[1] == "test"
    # . . push args
    68/push  "test"/imm32
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           8/disp8         .                 # push *(EBP+8)
    # . . call
    e8/call  kernel-string-equal?/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . check result
    3d/compare-EAX-and  1/imm32
    75/jump-if-not-equal  $run-main/disp8
    # . run-tests()
    e8/call  run-tests/disp32
    8b/copy                         0/mod/indirect  5/rm32/.disp32            .             .           3/r32/EBX   Num-test-failures/disp32          # copy *Num-test-failures to EBX
    eb/jump  $main:end/disp8
$run-main:
    # - otherwise convert stdin
    # var ed/EAX : exit-descriptor
    81          5/subop/subtract    3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # subtract from ESP
    89/copy                         3/mod/direct    0/rm32/EAX    .           .             .           4/r32/ESP   .               .                 # copy ESP to EAX
    # configure ed to really exit()
    # . ed->target = 0
    c7          0/subop/copy        0/mod/direct    0/rm32/EAX    .           .             .           .           .               0/imm32           # copy to *EAX
    # return convert(Stdin, 1/stdout, 2/stderr, ed)
    # . . push args
    50/push-EAX/ed
    68/push  Stderr/imm32
    68/push  Stdout/imm32
    68/push  Stdin/imm32
    # . . call
    e8/call  convert/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x10/imm32        # add to ESP
    # . syscall(exit, 0)
    bb/copy-to-EBX  0/imm32
$main:end:
    b8/copy-to-EAX  1/imm32/exit
    cd/syscall  0x80/imm8

# data structures:
#   segment-info: {address, file-offset, size}            (12 bytes)
#   segments: (address stream {string, segment-info})     (16 bytes per row)
#   label-info: {segment-name, segment-offset, address}   (12 bytes)
#   labels: (address stream {string, label-info})         (16 bytes per row)
# these are all inefficient; use sequential scans for lookups

convert:  # in : (address buffered-file), out : (address buffered-file) -> <void>
    # pseudocode
    #   var segments = new-stream(10 rows, 16 bytes each)
    #   var labels = new-stream(512 rows, 16 bytes each)
    #   compute-offsets(in, segments, labels)
    #   compute-addresses(segments, labels)
    #   rewind-stream(in)
    #   emit-output(in, out, segments, labels)
    #
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # . save registers
    51/push-ECX
    52/push-EDX
    # var segments/ECX = stream(10 * 16)
    81          5/subop/subtract    3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xa0/imm32        # subtract from ESP
    68/push  0xa0/imm32/length
    68/push  0/imm32/read
    68/push  0/imm32/write
    89/copy                         3/mod/direct    1/rm32/ECX    .           .             .           4/r32/ESP   .               .                 # copy ESP to ECX
    # var labels/EDX = stream(512 * 16)
    81          5/subop/subtract    3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x2000/imm32      # subtract from ESP
    68/push  0x2000/imm32/length
    68/push  0/imm32/read
    68/push  0/imm32/write
    89/copy                         3/mod/direct    2/rm32/EDX    .           .             .           4/r32/ESP   .               .                 # copy ESP to EDX
    # compute-offsets(in, segments, labels)
    # . . push args
    52/push-EDX
    51/push-ECX
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           8/disp8         .                 # push *(EBP+8)
    # . . call
    e8/call  compute-offsets/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # compute-addresses(segments, labels)
    # . . push args
    52/push-EDX
    51/push-ECX
    # . . call
    e8/call  compute-addresses/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x10/imm32        # add to ESP
    # rewind-stream(in)
    # . . push args
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           8/disp8         .                 # push *(EBP+8)
    # . . call
    e8/call  rewind-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # emit-output(in, out, segments, labels)
    # . . push args
    52/push-EDX
    51/push-ECX
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0xc/disp8       .                 # push *(EBP+12)
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           8/disp8         .                 # push *(EBP+8)
    # . . call
    e8/call  emit-output/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x10/imm32        # add to ESP
$convert:end:
    # . reclaim locals
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x214/imm32       # add to ESP
    # . restore registers
    5a/pop-to-EDX
    59/pop-to-ECX
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

test-convert-computes-addresses:
    # input:
    #   == code 0x1
    #   ab x/imm32
    #   == data 0x1000
    #   x:
    #     01
    #
    # trace contains (in any order):
    #   label x is at address 0x1079
    #   segment code starts at address 0x74
    #   segment code has size 5
    #   segment data starts at address 0x1079
    #
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # setup
    # . clear-stream(_test-input-stream)
    # . . push args
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  clear-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # . clear-stream(_test-input-buffered-file+4)
    # . . push args
    b8/copy-to-EAX  _test-input-buffered-file/imm32
    05/add-to-EAX  4/imm32
    50/push-EAX
    # . . call
    e8/call  clear-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # . clear-stream(_test-output-stream)
    # . . push args
    68/push  _test-output-stream/imm32
    # . . call
    e8/call  clear-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # . clear-stream(_test-output-buffered-file+4)
    # . . push args
    b8/copy-to-EAX  _test-output-buffered-file/imm32
    05/add-to-EAX  4/imm32
    50/push-EAX
    # . . call
    e8/call  clear-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # initialize input
    # . write(_test-input-stream, "== code 0x1\n")
    # . . push args
    68/push  "== code 0x1\n"/imm32
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . write(_test-input-stream, "ab x/imm32\n")
    # . . push args
    68/push  "ab x/imm32\n"/imm32
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . write(_test-input-stream, "== data 0x1000\n")
    # . . push args
    68/push  "== data 0x1000\n"/imm32
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . write(_test-input-stream, "x:\n")
    # . . push args
    68/push  "x:\n"/imm32
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . write(_test-input-stream, "01\n")
    # . . push args
    68/push  "01\n"/imm32
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # convert(_test-input-buffered-file, _test-output-buffered-file)
    # . . push args
    68/push  _test-output-buffered-file/imm32
    68/push  _test-input-buffered-file/imm32
    # . . call
    e8/call  convert/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # check trace
    # . check-trace-contains("label 'x' is at address 0x1079", msg)
    # . . push args
    68/push  "F - test-convert-computes-addresses/0"/imm32
    68/push  "label 'x' is at address 0x1079"/imm32
    # . . call
    e8/call  check-trace-contains/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . check-trace-contains("segment 'code' starts at address 0x74", msg)
    # . . push args
    68/push  "F - test-convert-computes-addresses/1"/imm32
    68/push  "segment 'code' starts at address 0x74"/imm32
    # . . call
    e8/call  check-trace-contains/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . check-trace-contains("segment 'code' has size 0x5", msg)
    # . . push args
    68/push  "F - test-convert-computes-addresses/2"/imm32
    68/push  "segment 'code' has size 0x5"/imm32
    # . . call
    e8/call  check-trace-contains/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . check-trace-contains("segment 'data' starts at address 0x1079", msg)
    # . . push args
    68/push  "F - test-convert-computes-addresses/3"/imm32
    68/push  "segment 'data' starts at address 0x1079"/imm32
    # . . call
    e8/call  check-trace-contains/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

# global scratch space for compute-offsets in the data segment
== data

compute-offsets:curr-segment-name: 0/imm32/curr
compute-offsets:curr-segment-name:end: 0/imm32/limit
compute-offsets:file-offset: 0/imm32
compute-offsets:segment-offset: 0/imm32
compute-offsets:word-slice: 0/imm32/curr
compute-offsets:word-slice:end: 0/imm32/limit
compute-offsets:heap: 0/imm32/curr
compute-offsets:heap:end: 0/imm32/limit

== code

compute-offsets:  # in : (address buffered-file), segments : (address stream {string, segment-info}), labels : (address stream {string, label-info})
    # pseudocode:
    #   var curr-segment-name = 0
    #   var file-offset = 0, segment-offset = 0
    #   var line = new-stream(512, 1)
    #   while true                                  # line loop
    #     clear-stream(line)
    #     read-line-buffered(in, line)
    #     if (line->write == 0) break               # end of file
    #     while true                                # word loop
    #       var word-slice = next-word(line)
    #       if slice-empty?(word-slice)             # end of line
    #         break
    #       if slice-starts-with?(word-slice, "#")  # comment
    #         continue
    #       if is-label?(word-slice)
    #         x : (address number) = insert(labels, name)
    #         *x = segment-offset
    #         trace("label '", word-slice, "' is in segment '", curr-segment-name, "'")
    #         trace("label '", word-slice, "' is at offset 0x", file-offset)
    #         # labels occupy no space, so no need to increment offsets
    #         continue
    #       if slice-equal?(word-slice, "==")
    #         if curr-segment-name != 0
    #           seg = get-or-insert(segments, curr-segment-name)
    #           seg->size = *file-offset - seg->starting-offset
    #           trace("segment '", curr-segment-name, "' has size 0x", seg->size)
    #         curr-segment-name = next-word(line)
    #         if slice-empty?(curr-segment-name)
    #           abort
    #         segment-start = next-word(line)
    #         if slice-empty?(segment-start)
    #           abort
    #         seg = get-or-insert(segments, curr-segment-name)
    #         seg->starting-address = parse-hex-int(segment-start)
    #         seg->starting-offset = *file-offset
    #         trace("segment '", curr-segment-name, "' is at file offset 0x", seg->starting-offset)
    #         segment-offset = 0
    #       else
    #         width = compute-width(word-slice)
    #         *segment-offset += width
    #         *file-offset += width
    #
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # . save registers
    50/push-EAX
    51/push-ECX
    52/push-EDX
    53/push-EBX
    56/push-ESI
    57/push-EDI
    # curr-segment-name = {0, 0}
    c7          0/subop/copy        0/mod/indirect  5/rm32/.disp32            .             .           .           compute-offsets:curr-segment-name/disp32  0/imm32        # copy to *compute-offsets:word-slice
    c7          0/subop/copy        0/mod/indirect  5/rm32/.disp32            .             .           .           compute-offsets:curr-segment-name:end/disp32  0/imm32    # copy to *(compute-offsets:word-slice+4)
    # file-offset = 0
    b8/copy-to-EAX  0/imm32
    89/copy                         0/mod/indirect  5/rm32/.disp32            .             .           0/r32/EAX   compute-offsets:file-offset/disp32      # copy EAX to *file-offset
    # segment-offset = 0
    b8/copy-to-EAX  0/imm32
    89/copy                         0/mod/indirect  5/rm32/.disp32            .             .           0/r32/EAX   compute-offsets:segment-offset/disp32      # copy EAX to *segment-offset
    # var heap : (address allocation-descriptor) = {0, 0}
    c7          0/subop/copy        0/mod/indirect  5/rm32/.disp32            .             .           .           compute-offsets:heap/disp32  0/imm32        # copy to *compute-offsets:word-slice
    c7          0/subop/copy        0/mod/indirect  5/rm32/.disp32            .             .           .           compute-offsets:heap:end/disp32  0/imm32    # copy to *(compute-offsets:word-slice+4)
    # new-segment(1024, heap)
    # . . push args
    68/push  compute-offsets:heap/imm32
    68/push  0x400/imm32
    # . . call
    e8/call  new-segment/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # line/ECX = new-stream(heap, 512, 1)
    68/push  1/imm32
    68/push  0x200/imm32
    68/push  compute-offsets:heap/imm32
    e8/call  new-stream/disp32
    # . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # . line/ECX = EAX
    89/copy                         3/mod/direct    1/rm32/ECX    .           .             .           0/r32/EAX   .               .                 # copy EAX to ECX
$compute-offsets:line-loop:
    # clear-stream(line/ECX)
    51/push-ECX
    e8/call  clear-stream/disp32
    # . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # read-line-buffered(in, line/EAX)
    51/push-ECX
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           8/disp8         .                 # push *(EBP+8)
    e8/call  read-line-buffered/disp32
    # . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # if(line->write == 0)
    # . EAX = line/ECX->write
    8b/copy                         0/mod/indirect  1/rm32/ECX    .           .             .           0/r32/EAX   .               .                 # copy *ECX to EAX
    # . line->write/EAX == 0 ?
    3d/compare-EAX-and  0/imm32
    # . if so, break
    0f 84/jump-if-equal  $compute-offsets:end/disp32
$compute-offsets:word-loop:
    # var word-slice/EDX = {0, 0}
    c7          0/subop/copy        0/mod/indirect  5/rm32/.disp32            .             .           .           compute-offsets:word-slice/disp32  0/imm32        # copy to *compute-offsets:word-slice
    c7          0/subop/copy        0/mod/indirect  5/rm32/.disp32            .             .           .           compute-offsets:word-slice:end/disp32  0/imm32    # copy to *(compute-offsets:word-slice+4)
    ba/copy-to-EDX  compute-offsets:word-slice/imm32
    # next-word(line/ECX, word-slice/EDX)
    52/push-EDX
    51/push-ECX
    e8/call  next-word/disp32
    # . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # if slice-empty?(word/EDX) break
    # . EAX = slice-empty?(word/EDX)
    52/push-EDX
    e8/call  slice-empty?/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # . EAX == 1 ?
    3d/compare-EAX-and  1/imm32
    # . if so, break (go to top of outer loop)
    0f 84/jump-if-equal  $compute-offsets:line-loop/disp32
    # if slice-starts-with?(word-slice, "#") continue
    68/push  "#"/imm32
    52/push-EDX
    e8/call  slice-starts-with?/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . EAX == 1 ?
    3d/compare-EAX-and  1/imm32
    # . if so, continue
    74/jump-if-equal  $compute-offsets:word-loop/disp8
$compute-offsets:label:
    # if is-label?(word-slice/EDX)
    # . EAX = is-label?(word-slice/EDX)
    52/push-EDX
    e8/call  is-label?/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # . EAX == 0 ?
    3d/compare-EAX-and  0/imm32
    # . if so, goto segment check
    74/jump-if-equal  $compute-offsets:segment/disp8
    # . else fallthrough
    # x = insert(labels, word-slice)
    # . EAX = get-or-insert(labels, word-slice/EDX, row-size=16)
    # . . push args
    68/push  0x10/imm32/row-size
    52/push-EDX
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0x10/disp8      .                 # push *(EBP+16)
    # . . call
    e8/call  get-or-insert/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # trace-slsls("label '" word-slice/EDX "' is in segment '" current-segment-name "'")
    # . . push args
    68/push  "'"/imm32
    68/push  compute-offsets:curr-segment-name/imm32
    68/push  "' is in segment '"/imm32
    52/push-EDX
    68/push  "label '"/imm32
    # . . call
    e8/call  trace-slsls/disp32
    # trace-slsns("label '" word-slice/EDX "' is at offset '" *file-offset/EAX "'")
    # . . EAX = file-offset
    b8/copy-to-EAX compute-offsets:file-offset/imm32
    # . . EAX = *file-offset/EAX
    8b/copy                         0/mod/indirect  0/rm32/EAX    .           .             .           0/r32/EAX   .               .                 # copy *EAX to EAX
    # . . push args
    68/push  "."/imm32
    50/push-EAX
    68/push  "' is at offset "/imm32
    52/push-EDX
    68/push  "label '"/imm32
    # . . call
    e8/call  trace-slsns/disp32
    # continue
    e9/jump  $compute-offsets:word-loop/disp32
$compute-offsets:segment:
    # if slice-equal?(word-slice/EDX, "==")
    # . EAX = slice-equal?(word-slice/EDX, "==")
    68/push  "=="/imm32
    52/push-EDX
    e8/call  slice-equal?/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . EAX == 0 ?
    3d/compare-EAX-and  0/imm32
    # . if so, goto else
    0f 84/jump-if-equal  $compute-offsets:else/disp32
    # . or fallthrough
    # if curr-segment-name == 0, goto construct-next-segment
    8b/copy                         0/mod/indirect  5/rm32/.disp32            .             .           0/r32/EAX   compute-offsets:curr-segment-name/disp32 # copy *curr-segment-name to EAX
    3d/compare-EAX-and  0/imm32
    74/jump-if-equal  $compute-offsets:construct-next-segment/disp8
    # EAX = slice-to-string(curr-segment-name)
    68/push  compute-offsets:curr-segment-name/imm32
    68/push  compute-offsets:heap/imm32
    e8/call  slice-to-string/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # seg/EAX = get-or-insert(segments, (string) curr-segment-name/EAX, row-size=16)
    # . push args
    68/push  0x10/imm32/row-size
    50/push-EAX
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0xc/disp8       .                 # push *(EBP+12)
    # . call
    e8/call  get-or-insert/disp32
    # . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # seg->size/EBX = file-offset - seg->starting-offset
    # . save ECX
    51/push-ECX
    # . EBX = *file-offset
    8b/copy                         0/mod/indirect  5/rm32/.disp32            .             .           3/r32/EBX   compute-offsets:file-offset/disp32 # copy *file-offset to EBX
    # . ECX = seg->starting-offset
    8b/copy                         1/mod/*+disp8   0/rm32/EAX    .           .             .           1/r32/ECX   4/disp8         .                 # copy *(EAX+4) to ECX
    # . EBX -= ECX
    29/subtract                     3/mod/direct    3/rm32/EBX    .           .             .           1/r32/ECX   .               .                 # subtract ECX from EBX
    # . seg->size = EBX
    89/copy                         1/mod/*+disp8   0/rm32/EAX    .           .             .           3/r32/EBX   8/disp8         .                 # copy EBX to *(EAX+8)
    # . restore ECX
    59/pop-to-ECX
    # trace-slsns("segment '", curr-segment-name, "' has size 0x", seg->size/EBX, "")
    # . push args
    68/push  "."/imm32
    53/push-EBX
    68/push  "' has size "/imm32
    68/push  compute-offsets:curr-segment-name/imm32
    68/push  "segment '"/imm32
    # . call
    e8/call  trace-slsns/disp32
    # . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x14/imm32        # add to ESP
$compute-offsets:construct-next-segment:
    # next-word(line/ECX, curr-segment-name)
    68/push  compute-offsets:curr-segment-name/imm32
    51/push-ECX
    e8/call  next-word/disp32
    # . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # if slice-empty?(curr-segment-name) abort
    # . EAX = slice-empty?(curr-segment-name)
    68/push  compute-offsets:curr-segment-name/imm32
    e8/call  slice-empty?/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # . EAX == 1 ?
    3d/compare-EAX-and  1/imm32
    # . if so, abort
    0f 84/jump-if-equal  $compute-offsets:abort/disp32
    # segment-start/EBX = {0, 0}
    68/push  0/imm32
    68/push  0/imm32
    89/copy                         3/mod/direct    3/rm32/EBX    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBX
    # next-word(line/ECX, segment-start/EBX)
    53/push-EBX
    51/push-ECX
    e8/call  next-word/disp32
    # . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # if slice-empty?(segment-start/EBX) abort
    # . EAX = slice-empty?(segment-start/EBX)
    53/push-EBX
    e8/call  slice-empty?/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # . EAX == 1 ?
    3d/compare-EAX-and  1/imm32
    # . if so, abort
    0f 84/jump-if-equal  $compute-offsets:abort/disp32
    # save segment-start/EBX (and prep for parse-hex-int call)
    53/push-EBX
    # EAX = slice-to-string(curr-segment-name)
    68/push  compute-offsets:curr-segment-name/imm32
    68/push  compute-offsets:heap/imm32
    e8/call  slice-to-string/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # seg/EBX = get-or-insert(segments, (string) curr-segment-name/EAX, row-size=16)
    # . push args
    68/push  0x10/imm32/row-size
    50/push-EAX
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0xc/disp8       .                 # push *(EBP+12)
    e8/call  get-or-insert/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # . EBX = EAX
    89/copy                         3/mod/direct    3/rm32/EBX    .           .             .           0/r32/EAX   .               .                 # copy EAX to EBX
    # seg->address = parse-hex-int(segment-start (already on stack))
    # . EAX = parse-hex-int(segment-start)
    e8/call  parse-hex-int/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # . seg->address = EAX
    89/copy                         0/mod/indirect  3/rm32/EBX    .           .             .           0/r32/EAX   .               .                 # copy EAX to *EBX
    # seg->file-offset = *file-offset/EAX
    # . EAX = *file-offset
    b8/copy-to-EAX  compute-offsets:file-offset/imm32
    8b/copy                         0/mod/indirect  0/rm32/EAX    .           .             .           0/r32/EAX   .               .                 # copy *EAX to EAX
    89/copy                         1/mod/*+disp8   3/rm32/EBX    .           .             .           0/r32/EAX   4/disp8         .                 # copy EAX to *(EBX+4)
    # trace-slsns("segment '", curr-segment-name, "' is at file offset ", seg->file-offset/EAX, "")
    # . push args
    68/push  "."/imm32
    50/push-EAX
    68/push  "' is at file offset "/imm32
    68/push  compute-offsets:curr-segment-name/imm32
    68/push  "segment '"/imm32
    # . call
    e8/call  trace-slsns/disp32
    # . discard args
    # segment-offset = 0
    c7          0/subop/copy        0/mod/indirect  5/rm32/.disp32            .             .           .     compute-offsets:segment-offset/disp32  0/imm32           # copy to *segment-offset
    e9/jump $compute-offsets:line-loop/disp32
$compute-offsets:else:
    # EAX = slice-to-string(curr-segment-name)
    52/push-EDX
    68/push  compute-offsets:heap/imm32
    e8/call  slice-to-string/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # width/EAX = compute-width(word/EAX)
    50/push-EAX
    e8/call compute-width/disp32
    # . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # segment-offset += width
    # . EBX = *segment-offset
    8b/copy                         0/mod/indirect  5/rm32/.disp32            .             .           3/r32/EBX   compute-offsets:segment-offset/disp32 # copy *segment-offset to EBX
    # . *segment-offset/EBX += EAX/width
    03/add                          3/mod/direct    0/rm32/EAX    .           .             .           3/r32/EBX   .               .                 # add EAX to EBX
    89/copy                         0/mod/indirect  5/rm32/.disp32            .             .           3/r32/EBX   compute-offsets:segment-offset/disp32 # copy EBX to *compute-offsets:segment-offset
    # file-offset += width
    # . EBX = *file-offset
    8b/copy                         0/mod/indirect  5/rm32/.disp32            .             .           3/r32/EBX   compute-offsets:file-offset/disp32 # copy *file-offset to EBX
    # . *file-offset/EBX += EAX/width
    03/add                          3/mod/direct    0/rm32/EAX    .           .             .           3/r32/EBX   .               .                 # add EAX to EBX
    89/copy                         0/mod/indirect  5/rm32/.disp32            .             .           3/r32/EBX   compute-offsets:file-offset/disp32 # copy EBX to *compute-offsets:file-offset
    e9/jump $compute-offsets:line-loop/disp32
$compute-offsets:end:
    # . reclaim locals
    # . restore registers
    5f/pop-to-EDI
    5e/pop-to-ESI
    5b/pop-to-EBX
    5a/pop-to-EDX
    59/pop-to-ECX
    58/pop-to-EAX
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return
$compute-offsets:abort:
    # . _write(2/stderr, error)
    # . . push args
    68/push  "'==' must be followed by segment name and segment-start\n"/imm32
    68/push  2/imm32/stderr
    # . . call
    e8/call  _write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . syscall(exit, 1)
    bb/copy-to-EBX  1/imm32
    b8/copy-to-EAX  1/imm32/exit
    cd/syscall  0x80/imm8
    # never gets here

test-compute-offsets:
    # input:
    #   == code 0x1
    #   ab x/imm32
    #   == data 0x1000
    #   x:
    #     34
    #
    # trace contains (in any order):
    #   segment 'code' is at file offset 0x0
    #   segment 'code' has size 0x5
    #   segment 'data' is at file offset 0x5
    #   label 'x' is in segment 'data'
    #   label 'x' is at offset 0x0
    #   segment 'data' has size 0x1
    #
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # setup
    # . clear-stream(_test-input-stream)
    # . . push args
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  clear-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # . clear-stream(_test-input-buffered-file+4)
    # . . push args
    b8/copy-to-EAX  _test-input-buffered-file/imm32
    05/add-to-EAX  4/imm32
    50/push-EAX
    # . . call
    e8/call  clear-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # . clear-stream(_test-output-stream)
    # . . push args
    68/push  _test-output-stream/imm32
    # . . call
    e8/call  clear-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # . clear-stream(_test-output-buffered-file+4)
    # . . push args
    b8/copy-to-EAX  _test-output-buffered-file/imm32
    05/add-to-EAX  4/imm32
    50/push-EAX
    # . . call
    e8/call  clear-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # var segments/ECX = stream(2 * 16)
    81          5/subop/subtract    3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x20/imm32        # subtract from ESP
    68/push  0x20/imm32/length
    68/push  0/imm32/read
    68/push  0/imm32/write
    89/copy                         3/mod/direct    1/rm32/ECX    .           .             .           4/r32/ESP   .               .                 # copy ESP to ECX
    # var labels/EDX = stream(2 * 16)
    81          5/subop/subtract    3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x20/imm32        # subtract from ESP
    68/push  0x20/imm32/length
    68/push  0/imm32/read
    68/push  0/imm32/write
    89/copy                         3/mod/direct    2/rm32/EDX    .           .             .           4/r32/ESP   .               .                 # copy ESP to EDX
    # initialize input
    # . write(_test-input-stream, "== code 0x1\n")
    # . . push args
    68/push  "== code 0x1\n"/imm32
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . write(_test-input-stream, "ab x/imm32\n")
    # . . push args
    68/push  "ab x/imm32\n"/imm32
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . write(_test-input-stream, "== data 0x1000\n")
    # . . push args
    68/push  "== data 0x1000\n"/imm32
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . write(_test-input-stream, "x:\n")
    # . . push args
    68/push  "x:\n"/imm32
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . write(_test-input-stream, "34\n")
    # . . push args
    68/push  "34\n"/imm32
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # compute-offsets(_test-input-buffered-file, segments, labels)
    # . . push args
    52/push-EDX
    51/push-ECX
    68/push  _test-input-buffered-file/imm32
    # . . call
    e8/call  compute-offsets/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32        # add to ESP
    # check trace
    # . check-trace-contains("segment 'code' is at file offset 0x00000000.", msg)
    # . . push args
    68/push  "F - test-compute-offsets/0"/imm32
    68/push  "segment 'code' is at file offset 0x00000000."/imm32
    # . . call
    e8/call  check-trace-contains/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . check-trace-contains("segment 'code' has size 0x5", msg)
    # . . push args
    68/push  "F - test-compute-offsets/1"/imm32
    68/push  "segment 'code' has size 0x5"/imm32
    # . . call
    e8/call  check-trace-contains/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . check-trace-contains("segment 'data' is at file offset 0x5", msg)
    # . . push args
    68/push  "F - test-compute-offsets/2"/imm32
    68/push  "segment 'data' is at file offset 0x5"/imm32
    # . . call
    e8/call  check-trace-contains/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . check-trace-contains("segment 'data' has size 0x1", msg)
    # . . push args
    68/push  "F - test-compute-offsets/3"/imm32
    68/push  "segment 'data' has size 0x1"/imm32
    # . . call
    e8/call  check-trace-contains/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . check-trace-contains("label 'x' is in segment 'data'", msg)
    # . . push args
    68/push  "F - test-compute-offsets/4"/imm32
    68/push  "label 'x' is in segment 'data'"/imm32
    # . . call
    e8/call  check-trace-contains/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . check-trace-contains("label 'x' is at offset 0x0", msg)
    # . . push args
    68/push  "F - test-compute-offsets/5"/imm32
    68/push  "label 'x' is at offset 0x0"/imm32
    # . . call
    e8/call  check-trace-contains/disp32
     # dump *Trace-stream {{{
     # . write(2/stderr, "^")
     # . . push args
     68/push  "^"/imm32
     68/push  2/imm32/stderr
     # . . call
     e8/call  write/disp32
     # . . discard args
     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
     # . write-stream(2/stderr, *Trace-stream)
     # . . push args
     ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # push *Trace-stream
     68/push  2/imm32/stderr
     # . . call
     e8/call  write-stream/disp32
     # . . discard args
     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
     # . write(2/stderr, "$\n")
     # . . push args
     68/push  "$\n"/imm32
     68/push  2/imm32/stderr
     # . . call
     e8/call  write/disp32
     # . . discard args
     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
     # }}}
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

compute-addresses:  # segments : (address stream {string, segment-info}), labels : (address stream {string, label-info})
    # pseudocode:
    #   srow : (address segment-info) = segments->data
    #   max = segments->data + segments->write
    #   num-segments = segments->write / 16
    #   starting-offset = 0x34 + (num-segments * 0x20)
    #   while true
    #     if (srow >= max) break
    #     s->file-offset += starting-offset
    #     s->address &= 0xfffff000  # clear last 12 bits for p_align
    #     s->address += (s->file-offset & 0x00000fff)
    #     trace-sssns("segment " s->key " starts at address " s->address)
    #     srow += 16  # row-size
    #   lrow : (address label-info) = labels->data
    #   max = labels->data + labels->write
    #   while true
    #     if (lrow >= max) break
    #     seg-name : (address string) = lrow->segment-name
    #     label-seg : (address segment-info) = get-or-insert(segments, seg-name, row-size=16)
    #     lrow->address = label-seg->address + lrow->segment-offset
    #     trace-sssns("label " lrow->key " is at address " lrow->address)
    #     lrow += 16  # row-size
    #
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # . save registers
    50/push-EAX
    51/push-ECX
    52/push-EDX
    53/push-EBX
    56/push-ESI
    57/push-EDI
    # ESI = segments
    8b/copy                         1/mod/*+disp8   5/rm32/EBP    .           .             .           6/r32/ESI   8/disp8         .                 # copy *(EBP+8) to ESI
    # starting-offset/EDI = 0x34 + (num-segments * 0x20)  # make room for ELF headers
    # . EDI = segments->write / 16 (row-size)
    8b/copy                         0/mod/indirect  6/rm32/ESI    .           .             .           7/r32/EDI   .               .                 # copy *ESI to EDI
    c1/shift    5/subop/logic-right 3/mod/direct    7/rm32/EDI    .           .             .           .           .               4/imm8            # shift EDI right by 4 bits, while padding zeroes
    # . EDI = (EDI * 0x20) + 0x34
    c1/shift    4/subop/left        3/mod/direct    7/rm32/EDI    .           .             .           .           .               5/imm8            # shift EDI left by 5 bits
    81          0/subop/add         3/mod/direct    7/rm32/EDI    .           .             .           .           .               0x34/imm32        # add to EDI
    # srow/EAX = segments->data
    8d/copy-address                 1/mod/*+disp8   6/rm32/ESI    .           .             .           0/r32/EAX   0xc/disp8       .                 # copy ESI+12 to EAX
    # max/ECX = segments->data + segments->write
    8b/copy                         0/mod/indirect  6/rm32/ESI    .           .             .           1/r32/ECX   .               .                 # copy *ESI to ECX
    01/add                          3/mod/direct    1/rm32/ECX    .           .             .           6/r32/ESI   .               .                 # add ESI to ECX
$compute-addresses:segment-loop:
    # if (srow >= max) break
    39/compare                      3/mod/direct    0/rm32/EAX    .           .             .           1/r32/ECX   .               .                 # compare EAX with ECX
    73/jump-if-greater-or-equal-unsigned  $compute-addresses:segment-break/disp8
    # srow->file-offset += starting-offset
    01/add                          1/mod/*+disp8   0/rm32/EAX    .           .             .           7/r32/EDI   8/disp8         .                 # add EDI to *(EAX+8)
    # clear last 12 bits of srow->address for p_align=0x1000
    # . EDX = srow->address
    8b/copy                         1/mod/*+disp8   0/rm32/EAX    .           .             .           2/r32/EDX   4/disp8         .                 # copy *(EAX+4) to EDX
    # . EDX &= 0xfffff000
    81          4/subop/and         3/mod/direct    2/rm32/EDX    .           .             .           .           .               0xfffff000/imm32  # bitwise and of EDX
    # update last 12 bits from srow->file-offset
    # . EBX = srow->file-offset
    8b/copy                         1/mod/*+disp8   0/rm32/EAX    .           .             .           3/r32/EBX   8/disp8         .                 # copy *(EAX+8) to EBX
    # . EBX &= 0xfff
    81          4/subop/and         3/mod/direct    3/rm32/EBX    .           .             .           .           .               0x00000fff/imm32  # bitwise and of EBX
    # . srow->address = EDX | EBX
    09/or                           3/mod/direct    2/rm32/EDX    .           .             .           3/r32/EBX   .               .                 # EDX = bitwise OR with EBX
    89/copy                         1/mod/*+disp8   0/rm32/EAX    .           .             .           2/r32/EDX   4/disp8         .                 # copy EDX to *(EAX+4)
    # trace-sssns("segment " srow " starts at address " srow->address ".")
    # . . push args
    68/push  "."/imm32
    52/push-EDX
    68/push  "' starts at address "/imm32
    ff          6/subop/push        0/mod/indirect  0/rm32/EAX    .           .             .           .           .               .                 # push *EAX
    68/push  "segment '"/imm32
    # . . call
    e8/call  trace-sssns/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x14/imm32        # add to ESP
    # srow += 16  # size of row
    05/add-to-EAX  0x10/imm32
    eb/jump  $compute-addresses:segment-loop/disp8
$compute-addresses:segment-break:
    # ESI = labels
    8b/copy                         1/mod/*+disp8   5/rm32/EBP    .           .             .           6/r32/ESI   0xc/disp8       .                 # copy *(EBP+12) to ESI
    # lrow/EAX = labels->data
    8d/copy-address                 1/mod/*+disp8   6/rm32/ESI    .           .             .           0/r32/EAX   0xc/disp8       .                 # copy ESI+12 to EAX
    # max/ECX = labels->data + labels->write
    8b/copy                         0/mod/indirect  6/rm32/ESI    .           .             .           1/r32/ECX   .               .                 # copy *ESI to ECX
    01/add                          3/mod/direct    1/rm32/ECX    .           .             .           6/r32/ESI   .               .                 # add ESI to ECX
$compute-addresses:label-loop:
    # if (lrow >= max) break
    39/compare                      3/mod/direct    0/rm32/EAX    .           .             .           1/r32/ECX   .               .                 # compare EAX with ECX
    73/jump-if-greater-or-equal-unsigned  $compute-addresses:end/disp8
    # seg-name/EDX = lrow->segment-name
    8b/copy                         1/mod/*+disp8   0/rm32/EAX    .           .             .           2/r32/EDX   4/disp8         .                 # copy *EAX to EDX
    # label-seg/EDX : (address segment-info) = get-or-insert(segments, seg-name, row-size=16)
    # . save EAX
    50/push-EAX
    # . EAX = get-or-insert(segments, seg-name, row-size=16)
    # . . push args
    68/push  0x10/imm32/row-size
    52/push-EDX
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           8/disp8         .                 # push *(EBP+8)
    # . . call
    e8/call  get-or-insert/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # . EDX = EAX
    89/copy                         3/mod/direct    2/rm32/EDX    .           .             .           0/r32/EAX   .               .                 # copy EAX to EDX
    # . restore EAX
    58/pop-to-EAX
    # EBX = label-seg->address
    8b/copy                         0/mod/indirect  2/rm32/EDX    .           .             .           3/r32/EBX   .               .                 # copy *EDX to EBX
    # EBX += lrow->segment-offset
    03/add                          1/mod/*+disp8   0/rm32/EAX    .           .             .           3/r32/EBX   8/disp8         .                 # add *(EAX+8) to EBX
    # lrow->address = EBX
    89/copy                         1/mod/*+disp8   0/rm32/EAX    .           .             .           3/r32/EBX   0xc/disp8       .                 # copy EBX to *(EAX+12)
    # trace-sssns("label " lrow->key " is at address " lrow->address ".")
    # . . push args
    68/push  "."/imm32
    53/push-EBX
    68/push  "' is at address "/imm32
    ff          6/subop/push        0/mod/indirect  0/rm32/EAX    .           .             .           .           .               .                 # push *EAX
    68/push  "label '"/imm32
    # . . call
    e8/call  trace-sssns/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x14/imm32        # add to ESP
    # lrow += 16  # size of row
    05/add-to-EAX  0x10/imm32
    eb/jump  $compute-addresses:label-loop/disp8
$compute-addresses:end:
    # . restore registers
    5f/pop-to-EDI
    5e/pop-to-ESI
    5b/pop-to-EBX
    5a/pop-to-EDX
    59/pop-to-ECX
    58/pop-to-EAX
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

test-compute-addresses:
    # input:
    #   segments:
    #     - 'a': {0x1000, 0, 5}
    #     - 'b': {0x2018, 5, 1}
    #     - 'c': {0x5444, 6, 12}
    #   labels:
    #     - 'l1': {'a', 3, 0}
    #     - 'l2': {'b', 0, 0}
    #
    # trace contains in any order (comments in parens):
    #   segment 'a' starts at address 0x00001094.  (0x34 + 0x20 for each segment)
    #   segment 'b' starts at address 0x00002099.  (0x018 discarded)
    #   segment 'c' starts at address 0x0000509a.  (0x444 discarded)
    #   label 'l1' is at address 0x00001097.       (0x1094 + segment-offset 3)
    #   label 'l2' is at address 0x00002099.       (0x2099 + segment-offset 0)
    #
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # setup
    # . var segments/ECX = stream(10 * 16)
    81          5/subop/subtract    3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xa0/imm32        # subtract from ESP
    68/push  0xa0/imm32/length
    68/push  0/imm32/read
    68/push  0/imm32/write
    89/copy                         3/mod/direct    1/rm32/ECX    .           .             .           4/r32/ESP   .               .                 # copy ESP to ECX
    # . var labels/EDX = stream(512 * 16)
    81          5/subop/subtract    3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x2000/imm32      # subtract from ESP
    68/push  0x2000/imm32/length
    68/push  0/imm32/read
    68/push  0/imm32/write
    89/copy                         3/mod/direct    2/rm32/EDX    .           .             .           4/r32/ESP   .               .                 # copy ESP to EDX
    # . stream-add4(segments, "a", 0x1000, 0, 5)
    68/push  5/imm32/segment-size
    68/push  0/imm32/file-offset
    68/push  0x1000/imm32/start-address
    68/push  "a"/imm32/segment-name
    51/push-ECX
    # . . call
    e8/call  stream-add4/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x14/imm32        # add to ESP
    # . stream-add4(segments, "b", 0x2018, 5, 1)
    68/push  1/imm32/segment-size
    68/push  5/imm32/file-offset
    68/push  0x2018/imm32/start-address
    68/push  "b"/imm32/segment-name
    51/push-ECX
    # . . call
    e8/call  stream-add4/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x14/imm32        # add to ESP
    # . stream-add4(segments, "c", 0x5444, 6, 12)
    68/push  0xc/imm32/segment-size
    68/push  6/imm32/file-offset
    68/push  0x5444/imm32/start-address
    68/push  "c"/imm32/segment-name
    51/push-ECX
    # . . call
    e8/call  stream-add4/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x14/imm32        # add to ESP
    # . stream-add4(labels, "l1", "a", 3, 0)
    68/push  0/imm32/label-address
    68/push  3/imm32/segment-offset
    68/push  "a"/imm32/segment-name
    68/push  "l1"/imm32/label-name
    52/push-EDX
    # . . call
    e8/call  stream-add4/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x14/imm32        # add to ESP
    # . stream-add4(labels, "l2", "b", 0, 0)
    68/push  0/imm32/label-address
    68/push  0/imm32/segment-offset
    68/push  "b"/imm32/segment-name
    68/push  "l2"/imm32/label-name
    52/push-EDX
    # . . call
    e8/call  stream-add4/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x14/imm32        # add to ESP
    # component under test
    # . compute-addresses(segments, labels)
    # . . push args
    52/push-EDX
    51/push-ECX
    # . . call
    e8/call  compute-addresses/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # checks
#?     # dump *Trace-stream {{{
#?     # . write(2/stderr, "^")
#?     # . . push args
#?     68/push  "^"/imm32
#?     68/push  2/imm32/stderr
#?     # . . call
#?     e8/call  write/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
#?     # . write-stream(2/stderr, *Trace-stream)
#?     # . . push args
#?     ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # push *Trace-stream
#?     68/push  2/imm32/stderr
#?     # . . call
#?     e8/call  write-stream/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
#?     # . write(2/stderr, "$\n")
#?     # . . push args
#?     68/push  "$\n"/imm32
#?     68/push  2/imm32/stderr
#?     # . . call
#?     e8/call  write/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
#?     # }}}
    # . check-trace-contains("segment 'a' starts at address 0x00001094.", msg)
    # . . push args
    68/push  "F - test-compute-addresses/0"/imm32
    68/push  "segment 'a' starts at address 0x00001094."/imm32
    # . . call
    e8/call  check-trace-contains/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . check-trace-contains("segment 'b' starts at address 0x00002099.", msg)
    # . . push args
    68/push  "F - test-compute-addresses/1"/imm32
    68/push  "segment 'b' starts at address 0x00002099."/imm32
    # . . call
    e8/call  check-trace-contains/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . check-trace-contains("segment 'c' starts at address 0x0000509a.", msg)
    # . . push args
    68/push  "F - test-compute-addresses/2"/imm32
    68/push  "segment 'c' starts at address 0x0000509a."/imm32
    # . . call
    e8/call  check-trace-contains/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . check-trace-contains("label 'l1' is at address 0x00001097.", msg)
    # . . push args
    68/push  "F - test-compute-addresses/3"/imm32
    68/push  "label 'l1' is at address 0x00001097."/imm32
    # . . call
    e8/call  check-trace-contains/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . check-trace-contains("label 'l2' is at address 0x00002099.", msg)
    # . . push args
    68/push  "F - test-compute-addresses/4"/imm32
    68/push  "label 'l2' is at address 0x00002099."/imm32
    # . . call
    e8/call  check-trace-contains/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

emit-output:  # in : (address buffered-file), out : (address buffered-file), segments : (address stream {string, segment-info}), labels : (address stream {string, label-info})
    # pseudocode:
    #   emit-headers(out, segments, labels)
    #   emit-segments(in, out, segments, labels)
    #
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # emit-headers(out, segments, labels)
    # . . push args
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0x14/disp8       .                # push *(EBP+20)
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0x10/disp8       .                # push *(EBP+16)
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0xc/disp8        .                # push *(EBP+12)
    # . . call
    e8/call  emit-headers/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # emit-segments(in, out, segments, labels)
    # . . push args
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0x14/disp8       .                # push *(EBP+20)
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0x10/disp8       .                # push *(EBP+16)
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0xc/disp8       .                 # push *(EBP+12)
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           8/disp8         .                 # push *(EBP+8)
    # . . call
    e8/call  emit-segments/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x10/imm32        # add to ESP
$emit-output:end:
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

emit-segments:  # in : (address buffered-file), out : (address buffered-file), segments : (address stream {string, segment-info}), labels : (address stream {string, label-info})
    # pseudocode:
    #   var offset-of-next-instruction = 0
    #   var line = new-stream(512, 1)
    #   while true
    #     clear-stream(line)
    #     read-line-buffered(in, line)
    #     if (line->write == 0) break               # end of file
    #     offset-of-next-instruction += num-bytes(line)
    #     while true
    #       var word-slice = next-word(line)
    #       if slice-empty?(word-slice)             # end of line
    #         break
    #       if slice-starts-with?(word-slice, "#")  # comment
    #         break
    #       if is-label?(word-slice)                # no need for label declarations anymore
    #         break
    #       if slice-equal?(word-slice, "==")
    #         break                                 # no need for segment header lines
    #       if length(word-slice) == 2
    #         write-slice-buffered(out, word-slice)
    #         write-buffered(out, " ")
    #         continue
    #       datum = next-token(word-slice, "/")
    #       info = get(labels, datum)
    #       if has-metadata?(word-slice, "imm8")
    #         abort  # label should never go to imm8
    #       else if has-metadata?(word-slice, "imm32")
    #         emit(out, info->address, 4)
    #       else if has-metadata?(word-slice, "disp8")
    #         value = info->offset - offset-of-next-instruction
    #         emit(out, value, 1)
    #       else if has-metadata?(word-slice, "disp32")
    #         value = info->offset - offset-of-next-instruction
    #         emit(out, value, 4)
    #       else
    #         abort
    #     write-buffered(out, "\n")
    #
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # . save registers
$emit-segments:end:
    # . reclaim locals
    # . restore registers
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

test-emit-segments:
    # input:
    #   in:
    #     == a 0x1000
    #     ab cd ef gh
    #     ij x/imm32
    #     == b 0x2000
    #     00
    #     x:
    #       34
    #   segments:
    #     - 'a': {0x1074, 0, 5}
    #     - 'b': {0x2079, 5, 1}
    #   labels:
    #     - 'l1': {'a', 3, 0x1077}
    #     - 'l2': {'b', 1, 0x207a}
    #
    # output:
    #   ab cd ef gh
    #   ij 19 20 00 00
    #   00
    #   34
    #
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # setup
    # . clear-stream(_test-input-stream)
    # . . push args
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  clear-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # . clear-stream(_test-input-buffered-file+4)
    # . . push args
    b8/copy-to-EAX  _test-input-buffered-file/imm32
    05/add-to-EAX  4/imm32
    50/push-EAX
    # . . call
    e8/call  clear-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # . clear-stream(_test-output-stream)
    # . . push args
    68/push  _test-output-stream/imm32
    # . . call
    e8/call  clear-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # . clear-stream(_test-output-buffered-file+4)
    # . . push args
    b8/copy-to-EAX  _test-output-buffered-file/imm32
    05/add-to-EAX  4/imm32
    50/push-EAX
    # . . call
    e8/call  clear-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # . var segments/ECX = stream(10 * 16)
    81          5/subop/subtract    3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xa0/imm32        # subtract from ESP
    68/push  0xa0/imm32/length
    68/push  0/imm32/read
    68/push  0/imm32/write
    89/copy                         3/mod/direct    1/rm32/ECX    .           .             .           4/r32/ESP   .               .                 # copy ESP to ECX
    # . var labels/EDX = stream(512 * 16)
    81          5/subop/subtract    3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x2000/imm32      # subtract from ESP
    68/push  0x2000/imm32/length
    68/push  0/imm32/read
    68/push  0/imm32/write
    89/copy                         3/mod/direct    2/rm32/EDX    .           .             .           4/r32/ESP   .               .                 # copy ESP to EDX
    # initialize input
    # . write(_test-input-stream, "== a 0x1000\n")
    # . . push args
    68/push  "== a 0x1000\n"/imm32
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . write(_test-input-stream, "ab cd ef gh\n")
    # . . push args
    68/push  "ab cd ef gh\n"/imm32
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . write(_test-input-stream, "ij x/imm32\n")
    # . . push args
    68/push  "ij x/imm32\n"/imm32
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . write(_test-input-stream, "== b 0x2000\n")
    # . . push args
    68/push  "== b 0x2000\n"/imm32
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . write(_test-input-stream, "00\n")
    # . . push args
    68/push  "00\n"/imm32
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . write(_test-input-stream, "x:\n")
    # . . push args
    68/push  "x:\n"/imm32
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . write(_test-input-stream, "34\n")
    # . . push args
    68/push  "34\n"/imm32
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . stream-add4(segments, "a", 0x1074, 0, 5)
    68/push  5/imm32/segment-size
    68/push  0/imm32/file-offset
    68/push  0x1074/imm32/start-address
    68/push  "a"/imm32/segment-name
    51/push-ECX
    # . . call
    e8/call  stream-add4/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x14/imm32        # add to ESP
    # . stream-add4(segments, "b", 0x2079, 5, 1)
    68/push  1/imm32/segment-size
    68/push  5/imm32/file-offset
    68/push  0x2079/imm32/start-address
    68/push  "b"/imm32/segment-name
    51/push-ECX
    # . . call
    e8/call  stream-add4/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x14/imm32        # add to ESP
    # . stream-add4(labels, "l1", "a", 3, 0x1077)
    68/push  0x1077/imm32/label-address
    68/push  3/imm32/segment-offset
    68/push  "a"/imm32/segment-name
    68/push  "l1"/imm32/label-name
    52/push-EDX
    # . . call
    e8/call  stream-add4/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x14/imm32        # add to ESP
    # . stream-add4(labels, "l2", "b", 1, 0x207a)
    68/push  0x207a/imm32/label-address
    68/push  1/imm32/segment-offset
    68/push  "b"/imm32/segment-name
    68/push  "l2"/imm32/label-name
    52/push-EDX
    # . . call
    e8/call  stream-add4/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x14/imm32        # add to ESP
    # component under test
    # . emit-segments(_test-input-buffered-file, _test-output-buffered-file, segments, labels)
    # . . push args
    52/push-EDX
    51/push-ECX
    68/push  _test-output-buffered-file/imm32
    68/push  _test-input-buffered-file/imm32
    # . . call
    e8/call  emit-segments/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x10/imm32        # add to ESP
    # checks
    # . check-next-stream-line-equal(_test-output-stream, "ab cd ef gh", msg)
    # . . push args
    68/push  "F - test-emit-segments/0"/imm32
    68/push  "ab cd ef gh"/imm32
    68/push  _test-output-stream/imm32
    # . . call
    e8/call  check-next-stream-line-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # . check-next-stream-line-equal(_test-output-stream, "ij 19 20 00 00", msg)
    # . . push args
    68/push  "F - test-emit-segments/1"/imm32
    68/push  "ij 19 20 00 00"/imm32
    68/push  _test-output-stream/imm32
    # . . call
    e8/call  check-next-stream-line-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # . check-next-stream-line-equal(_test-output-stream, "00", msg)
    # . . push args
    68/push  "F - test-emit-segments/2"/imm32
    68/push  "00"/imm32
    68/push  _test-output-stream/imm32
    # . . call
    e8/call  check-next-stream-line-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # . check-next-stream-line-equal(_test-output-stream, "34", msg)
    # . . push args
    68/push  "F - test-emit-segments/3"/imm32
    68/push  "34"/imm32
    68/push  _test-output-stream/imm32
    # . . call
    e8/call  check-next-stream-line-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

emit-headers:  # out : (address buffered-file), segments : (address stream {string, segment-info}), labels : (address stream {string, label-info})
    # pseudocode:
    #   emit-elf-header(out, segments, labels)
    #   curr-segment = segments->data
    #   max = segments->data + segments->write
    #   while true
    #     if (curr-segment >= max) break
    #     emit-elf-program-header-entry(curr-segment)
    #     curr-segment += 20                        # size of a row
    #
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # . save registers
$emit-headers:end:
    # . reclaim locals
    # . restore registers
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

emit-elf-header:  # out : (address buffered-file), segments : (address stream {string, segment-info}), labels : (address stream {string, label-info})
    # pseudocode
    #   *Elf_e_entry = get(labels, "Entry")->address
    #   *Elf_e_phnum = segments->write / 20         # size of a row
    #   write(out, Elf_header)
    #
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # . save registers
$emit-elf-header:end:
    # . reclaim locals
    # . restore registers
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

emit-elf-program-header-entry:  # curr-segment : {string, segment-info}
    # pseudocode:
    #   *Elf_p_offset = curr-segment->file-offset
    #   *Elf_p_vaddr = curr-segment->address
    #   *Elf_p_paddr = curr-segment->address
    #   *Elf_p_filesz = curr-segment->size
    #   *Elf_p_memsz = curr-segment->size
    #   if curr-segment->name == "code"
    #     *Elf_p_flags = 5  # r-x
    #   else
    #     *Elf_p_flags = 6  # rw-
    #   write(out, Elf_program_header_entry)
    #
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # . save registers
$emit-elf-program-header-entry:end:
    # . reclaim locals
    # . restore registers
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

# - some helpers for tests

stream-add4:  # in : (address stream byte), key : address, val1 : address, val2 : address, val3 : address
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # . save registers
    50/push-EAX
    51/push-ECX
    52/push-EDX
    56/push-ESI
    # ESI = in
    8b/copy                         1/mod/*+disp8   5/rm32/EBP    .           .             .           6/r32/ESI   8/disp8         .                 # copy *(EBP+8) to ESI
    # curr/EAX = in->data + in->write
    # . EAX = in->write
    8b/copy                         0/mod/indirect  6/rm32/ESI    .           .             .           0/r32/EAX   .               .                 # copy *ESI to EAX
    # . EAX = ESI+EAX+12
    8d/copy-address                 1/mod/*+disp8   4/rm32/sib    6/base/ESI  0/index/EAX   .           0/r32/EAX   0xc/disp8       .                 # copy ESI+EAX+12 to EAX
    # max/EDX = in->data + in->length
    # . EDX = in->length
    8b/copy                         1/mod/*+disp8   6/rm32/ESI    .           .             .           2/r32/EDX   8/disp8         .                 # copy *(ESI+8) to EDX
    # . EDX = ESI+EDX+12
    8d/copy-address                 1/mod/*+disp8   4/rm32/sib    6/base/ESI  2/index/EDX   .           2/r32/EDX   0xc/disp8       .                 # copy ESI+EDX+12 to EDX
    # if (curr >= max) abort
    39/compare                      3/mod/direct    0/rm32/EAX    .           .             .           2/r32/EDX   .               .                 # compare EAX with EDX
    73/jump-if-greater-or-equal-unsigned  $stream-add4:abort/disp8
    # *curr = key
    8b/copy                         1/mod/*+disp8   5/rm32/EBP    .           .                         1/r32/ECX   0xc/disp8       .                 # copy *(EBP+12) to ECX
    89/copy                         0/mod/indirect  0/rm32/EAX    .           .             .           1/r32/ECX   .               .                 # copy ECX to *EAX
    # curr += 4
    05/add-to-EAX  4/imm32
    # if (curr >= max) abort
    39/compare                      3/mod/direct    0/rm32/EAX    .           .             .           2/r32/EDX   .               .                 # compare EAX with EDX
    73/jump-if-greater-or-equal-unsigned  $stream-add4:abort/disp8
    # *curr = val1
    8b/copy                         1/mod/*+disp8   5/rm32/EBP    .           .                         1/r32/ECX   0x10/disp8      .                 # copy *(EBP+16) to ECX
    89/copy                         0/mod/indirect  0/rm32/EAX    .           .             .           1/r32/ECX   .               .                 # copy ECX to *EAX
    # curr += 4
    05/add-to-EAX  4/imm32
    # if (curr >= max) abort
    39/compare                      3/mod/direct    0/rm32/EAX    .           .             .           2/r32/EDX   .               .                 # compare EAX with EDX
    73/jump-if-greater-or-equal-unsigned  $stream-add4:abort/disp8
    # *curr = val2
    8b/copy                         1/mod/*+disp8   5/rm32/EBP    .           .                         1/r32/ECX   0x14/disp8      .                 # copy *(EBP+20) to ECX
    89/copy                         0/mod/indirect  0/rm32/EAX    .           .             .           1/r32/ECX   .               .                 # copy ECX to *EAX
    # curr += 4
    05/add-to-EAX  4/imm32
    # if (curr >= max) abort
    39/compare                      3/mod/direct    0/rm32/EAX    .           .             .           2/r32/EDX   .               .                 # compare EAX with EDX
    73/jump-if-greater-or-equal-unsigned  $stream-add4:abort/disp8
    # *curr = val3
    8b/copy                         1/mod/*+disp8   5/rm32/EBP    .           .                         1/r32/ECX   0x18/disp8      .                 # copy *(EBP+24) to ECX
    89/copy                         0/mod/indirect  0/rm32/EAX    .           .             .           1/r32/ECX   .               .                 # copy ECX to *EAX
    # in->write += 16
    81          0/subop/add         0/mod/indirect  6/rm32/ESI    .           .             .           .           .               0x10/imm32        # add to *ESI
$stream-add4:end:
    # . restore registers
    5e/pop-to-ESI
    5a/pop-to-EDX
    59/pop-to-ECX
    58/pop-to-EAX
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

$stream-add4:abort:
    # . _write(2/stderr, error)
    # . . push args
    68/push  "overflow in stream-add4\n"/imm32
    68/push  2/imm32/stderr
    # . . call
    e8/call  _write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . syscall(exit, 1)
    bb/copy-to-EBX  1/imm32
    b8/copy-to-EAX  1/imm32/exit
    cd/syscall  0x80/imm8
    # never gets here

# some variants of 'trace' that take multiple arguments in different combinations of types:
#   n: int
#   c: character [4-bytes, will eventually be UTF-8]
#   s: (address string)
#   l: (address slice)
# one gotcha: 's5' must not be empty

trace-sssns:  # s1 : (address string), s2 : (address string), s3 : (address string), n4 : int, s5 : (address string)
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # write(*Trace-stream, s1)
    # . . push args
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           8/disp8         .                 # push *(EBP+8)
    ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # push *Trace-stream
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # write(*Trace-stream, s2)
    # . . push args
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0xc/disp8       .                 # push *(EBP+12)
    ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # push *Trace-stream
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # write(*Trace-stream, s3)
    # . . push args
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0x10/disp8      .                 # push *(EBP+16)
    ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # push *Trace-stream
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # print-int32(*Trace-stream, n4)
    # . . push args
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0x14/disp8      .                 # push *(EBP+20)
    ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # push *Trace-stream
    # . . call
    e8/call  print-int32/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # trace(s5)  # implicitly adds a newline and finalizes the trace line
    # . . push args
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0x18/disp8      .                 # push *(EBP+24)
    # . . call
    e8/call  trace/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
$trace-sssns:end:
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

test-trace-sssns:
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # setup
    # . *Trace-stream->write = 0
    8b/copy                         0/mod/indirect  5/rm32/.disp32            .             .           0/r32/EAX   Trace-stream/disp32               # copy *Trace-stream to EAX
    c7          0/subop/copy        0/mod/direct    0/rm32/EAX    .           .             .           .           .               0/imm32           # clear *EAX
    # trace-sssns("A" "b" "c " 3 " e")
    # . . push args
    68/push  " e"/imm32
    68/push  3/imm32
    68/push  "c "/imm32
    68/push  "b"/imm32
    68/push  "A"/imm32
    # . . call
    e8/call  trace-sssns/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x14/imm32        # add to ESP
#?     # dump *Trace-stream {{{
#?     # . write(2/stderr, "^")
#?     # . . push args
#?     68/push  "^"/imm32
#?     68/push  2/imm32/stderr
#?     # . . call
#?     e8/call  write/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
#?     # . write-stream(2/stderr, *Trace-stream)
#?     # . . push args
#?     ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # push *Trace-stream
#?     68/push  2/imm32/stderr
#?     # . . call
#?     e8/call  write-stream/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
#?     # . write(2/stderr, "$\n")
#?     # . . push args
#?     68/push  "$\n"/imm32
#?     68/push  2/imm32/stderr
#?     # . . call
#?     e8/call  write/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
#?     # }}}
    # check-trace-contains("Abc 0x00000003 e")
    # . . push args
    68/push  "F - test-trace-sssns"/imm32
    68/push  "Abc 0x00000003 e"/imm32
    # . . call
    e8/call  check-trace-contains/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

trace-snsns:  # s1 : (address string), n2 : int, s3 : (address string), n4 : int, s5 : (address string)
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # write(*Trace-stream, s1)
    # . . push args
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           8/disp8         .                 # push *(EBP+8)
    ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # push *Trace-stream
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # print-int32(*Trace-stream, n2)
    # . . push args
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0xc/disp8       .                 # push *(EBP+12)
    ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # push *Trace-stream
    # . . call
    e8/call  print-int32/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # write(*Trace-stream, s3)
    # . . push args
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0x10/disp8      .                 # push *(EBP+16)
    ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # push *Trace-stream
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # print-int32(*Trace-stream, n4)
    # . . push args
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0x14/disp8      .                 # push *(EBP+20)
    ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # push *Trace-stream
    # . . call
    e8/call  print-int32/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # trace(s5)  # implicitly adds a newline and finalizes the trace line
    # . . push args
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0x18/disp8      .                 # push *(EBP+24)
    # . . call
    e8/call  trace/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
$trace-snsns:end:
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

test-trace-snsns:
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # setup
    # . *Trace-stream->write = 0
    8b/copy                         0/mod/indirect  5/rm32/.disp32            .             .           0/r32/EAX   Trace-stream/disp32               # copy *Trace-stream to EAX
    c7          0/subop/copy        0/mod/direct    0/rm32/EAX    .           .             .           .           .               0/imm32           # clear *EAX
    # trace-snsns("A " 2 " c " 3 " e")
    # . . push args
    68/push  " e"/imm32
    68/push  3/imm32
    68/push  " c "/imm32
    68/push  2/imm32
    68/push  "A "/imm32
    # . . call
    e8/call  trace-snsns/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x14/imm32        # add to ESP
#?     # dump *Trace-stream {{{
#?     # . write(2/stderr, "^")
#?     # . . push args
#?     68/push  "^"/imm32
#?     68/push  2/imm32/stderr
#?     # . . call
#?     e8/call  write/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
#?     # . write-stream(2/stderr, *Trace-stream)
#?     # . . push args
#?     ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # push *Trace-stream
#?     68/push  2/imm32/stderr
#?     # . . call
#?     e8/call  write-stream/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
#?     # . write(2/stderr, "$\n")
#?     # . . push args
#?     68/push  "$\n"/imm32
#?     68/push  2/imm32/stderr
#?     # . . call
#?     e8/call  write/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
#?     # }}}
    # check-trace-contains("Abc 0x00000003 e")
    # . . push args
    68/push  "F - test-trace-snsns"/imm32
    68/push  "A 0x00000002 c 0x00000003 e"/imm32
    # . . call
    e8/call  check-trace-contains/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

trace-slsls:  # s1 : (address string), l2 : (address slice), s3 : (address string), l4 : (address slice), s5 : (address string)
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # write(*Trace-stream, s1)
    # . . push args
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           8/disp8         .                 # push *(EBP+8)
    ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # push *Trace-stream
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # write-slice(*Trace-stream, l2)
    # . . push args
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0xc/disp8       .                 # push *(EBP+12)
    ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # push *Trace-stream
    # . . call
    e8/call  write-slice/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # write(*Trace-stream, s3)
    # . . push args
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0x10/disp8      .                 # push *(EBP+16)
    ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # push *Trace-stream
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # write-slice(*Trace-stream, l4)
    # . . push args
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0x14/disp8      .                 # push *(EBP+20)
    ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # push *Trace-stream
    # . . call
    e8/call  write-slice/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # trace(s5)  # implicitly adds a newline and finalizes the trace line
    # . . push args
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0x18/disp8      .                 # push *(EBP+24)
    # . . call
    e8/call  trace/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
$trace-slsls:end:
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

test-trace-slsls:
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # setup
    # . *Trace-stream->write = 0
    8b/copy                         0/mod/indirect  5/rm32/.disp32            .             .           0/r32/EAX   Trace-stream/disp32               # copy *Trace-stream to EAX
    c7          0/subop/copy        0/mod/direct    0/rm32/EAX    .           .             .           .           .               0/imm32           # clear *EAX
    # (EAX..ECX) = "b"
    b8/copy-to-EAX  "b"/imm32
    8b/copy                         0/mod/indirect  0/rm32/EAX    .           .             .           1/r32/ECX   .               .                 # copy *EAX to ECX
    8d/copy-address                 1/mod/*+disp8   4/rm32/sib    0/base/EAX  1/index/ECX   .           1/r32/ECX   4/disp8         .                 # copy EAX+ECX+4 to ECX
    05/add-to-EAX  4/imm32
    # var b/EBX : (address slice) = {EAX, ECX}
    51/push-ECX
    50/push-EAX
    89/copy                         3/mod/direct    3/rm32/EBX    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBX
    # (EAX..ECX) = "d"
    b8/copy-to-EAX  "d"/imm32
    8b/copy                         0/mod/indirect  0/rm32/EAX    .           .             .           1/r32/ECX   .               .                 # copy *EAX to ECX
    8d/copy-address                 1/mod/*+disp8   4/rm32/sib    0/base/EAX  1/index/ECX   .           1/r32/ECX   4/disp8         .                 # copy EAX+ECX+4 to ECX
    05/add-to-EAX  4/imm32
    # var d/EDX : (address slice) = {EAX, ECX}
    51/push-ECX
    50/push-EAX
    89/copy                         3/mod/direct    2/rm32/EDX    .           .             .           4/r32/ESP   .               .                 # copy ESP to EDX
    # trace-slsls("A" b "c" d "e")
    # . . push args
    68/push  "e"/imm32
    52/push-EDX
    68/push  "c"/imm32
    53/push-EBX
    68/push  "A"/imm32
    # . . call
    e8/call  trace-slsls/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x14/imm32        # add to ESP
#?     # dump *Trace-stream {{{
#?     # . write(2/stderr, "^")
#?     # . . push args
#?     68/push  "^"/imm32
#?     68/push  2/imm32/stderr
#?     # . . call
#?     e8/call  write/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
#?     # . write-stream(2/stderr, *Trace-stream)
#?     # . . push args
#?     ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # push *Trace-stream
#?     68/push  2/imm32/stderr
#?     # . . call
#?     e8/call  write-stream/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
#?     # . write(2/stderr, "$\n")
#?     # . . push args
#?     68/push  "$\n"/imm32
#?     68/push  2/imm32/stderr
#?     # . . call
#?     e8/call  write/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
#?     # }}}
    # check-trace-contains("Abcde")
    # . . push args
    68/push  "F - test-trace-slsls"/imm32
    68/push  "Abcde"/imm32
    # . . call
    e8/call  check-trace-contains/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

trace-slsns:  # s1 : (address string), l2 : (address slice), s3 : (address string), n4 : int, s5 : (address string)
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # write(*Trace-stream, s1)
    # . . push args
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           8/disp8         .                 # push *(EBP+8)
    ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # push *Trace-stream
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # write-slice(*Trace-stream, l2)
    # . . push args
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0xc/disp8       .                 # push *(EBP+12)
    ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # push *Trace-stream
    # . . call
    e8/call  write-slice/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # write(*Trace-stream, s3)
    # . . push args
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0x10/disp8      .                 # push *(EBP+16)
    ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # push *Trace-stream
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # print-int32(*Trace-stream, n4)
    # . . push args
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0x14/disp8      .                 # push *(EBP+20)
    ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # push *Trace-stream
    # . . call
    e8/call  print-int32/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # trace(s5)  # implicitly adds a newline and finalizes the trace line
    # . . push args
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0x18/disp8      .                 # push *(EBP+24)
    # . . call
    e8/call  trace/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
$trace-slsns:end:
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

test-trace-slsns:
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # setup
    # . *Trace-stream->write = 0
    8b/copy                         0/mod/indirect  5/rm32/.disp32            .             .           0/r32/EAX   Trace-stream/disp32               # copy *Trace-stream to EAX
    c7          0/subop/copy        0/mod/direct    0/rm32/EAX    .           .             .           .           .               0/imm32           # clear *EAX
    # (EAX..ECX) = "b"
    b8/copy-to-EAX  "b"/imm32
    8b/copy                         0/mod/indirect  0/rm32/EAX    .           .             .           1/r32/ECX   .               .                 # copy *EAX to ECX
    8d/copy-address                 1/mod/*+disp8   4/rm32/sib    0/base/EAX  1/index/ECX   .           1/r32/ECX   4/disp8         .                 # copy EAX+ECX+4 to ECX
    05/add-to-EAX  4/imm32
    # var b/EBX : (address slice) = {EAX, ECX}
    51/push-ECX
    50/push-EAX
    89/copy                         3/mod/direct    3/rm32/EBX    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBX
    # trace-slsls("A" b "c " 3 " e")
    # . . push args
    68/push  " e"/imm32
    68/push  3/imm32
    68/push  "c "/imm32
    53/push-EBX
    68/push  "A"/imm32
    # . . call
    e8/call  trace-slsns/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x14/imm32        # add to ESP
#?     # dump *Trace-stream {{{
#?     # . write(2/stderr, "^")
#?     # . . push args
#?     68/push  "^"/imm32
#?     68/push  2/imm32/stderr
#?     # . . call
#?     e8/call  write/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
#?     # . write-stream(2/stderr, *Trace-stream)
#?     # . . push args
#?     ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Trace-stream/disp32               # push *Trace-stream
#?     68/push  2/imm32/stderr
#?     # . . call
#?     e8/call  write-stream/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
#?     # . write(2/stderr, "$\n")
#?     # . . push args
#?     68/push  "$\n"/imm32
#?     68/push  2/imm32/stderr
#?     # . . call
#?     e8/call  write/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
#?     # }}}
    # check-trace-contains("Abc 0x00000003 e")
    # . . push args
    68/push  "F - test-trace-slsls"/imm32
    68/push  "Abc 0x00000003 e"/imm32
    # . . call
    e8/call  check-trace-contains/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

num-bytes:  # line : (address stream) -> EAX : int
    # pseudocode:
    #   result = 0
    #   while true
    #     var word-slice = next-word(line)
    #     if slice-empty?(word-slice)             # end of line
    #       break
    #     if slice-starts-with?(word-slice, "#")  # comment
    #       break
    #     if is-label?(word-slice)                # no need for label declarations anymore
    #       break
    #     if slice-equal?(word-slice, "==")
    #       break                                 # no need for segment header lines
    #     result += compute-width(word-slice)
    #   return result
    #
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # . save registers
    51/push-ECX
    52/push-EDX
    53/push-EBX
    # var result/EAX = 0
    31/xor                          3/mod/direct    0/rm32/EAX    .           .             .           0/r32/EAX   .               .                 # clear EAX
    # var word-slice/ECX = {0, 0}
    68/push  0/imm32/limit
    68/push  0/imm32/curr
    89/copy                         3/mod/direct    1/rm32/ECX    .           .             .           4/r32/ESP   .               .                 # copy ESP to ECX
#?     # dump line {{{
#?     # . write(2/stderr, "LL: ")
#?     # . . push args
#?     68/push  "LL: "/imm32
#?     68/push  2/imm32/stderr
#?     # . . call
#?     e8/call  write/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
#?     # write-stream(2/stderr, line)
#?     # . . push args
#?     ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           8/disp8         .                 # push *(EBP+8)
#?     68/push  2/imm32/stderr
#?     # . . call
#?     e8/call  write-stream/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
#?     # . write(2/stderr, "$\n")
#?     # . . push args
#?     68/push  "$\n"/imm32
#?     68/push  2/imm32/stderr
#?     # . . call
#?     e8/call  write/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
#?     # }}}
$num-bytes:loop:
    # next-word(line, word-slice)
    # . . push args
    51/push-ECX
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           8/disp8         .                 # push *(EBP+8)
    # . . call
    e8/call  next-word/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
#?     # dump word-slice {{{
#?     # . write(2/stderr, "AA: ")
#?     # . . push args
#?     68/push  "AA: "/imm32
#?     68/push  2/imm32/stderr
#?     # . . call
#?     e8/call  write/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
#?     # . clear-stream(Stderr+4)
#?     # . . save EAX
#?     50/push-EAX
#?     # . . push args
#?     b8/copy-to-EAX  Stderr/imm32
#?     05/add-to-EAX  4/imm32
#?     50/push-EAX
#?     # . . call
#?     e8/call  clear-stream/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
#?     # . . restore EAX
#?     58/pop-to-EAX
#?     # . write-slice-buffered(Stderr, word-slice)
#?     # . . push args
#?     51/push-ECX
#?     68/push  Stderr/imm32
#?     # . . call
#?     e8/call  write-slice-buffered/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
#?     # . flush(Stderr)
#?     # . . push args
#?     68/push  Stderr/imm32
#?     # . . call
#?     e8/call  flush/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
#?     # . write(2/stderr, "$\n")
#?     # . . push args
#?     68/push  "$\n"/imm32
#?     68/push  2/imm32/stderr
#?     # . . call
#?     e8/call  write/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
#?     # }}}
$num-bytes:check0:
    # if (slice-empty?(word-slice)) break
    # . save result
    50/push-EAX
    # . EAX = slice-empty?(word-slice)
    # . . push args
    51/push-ECX
    # . . call
    e8/call  slice-empty?/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # . if (EAX != 0) break
    3d/compare-EAX-and  0/imm32
    # . restore result now that ZF is set
    58/pop-to-EAX
    75/jump-if-not-equal  $num-bytes:end/disp8
$num-bytes:check-for-comment:
    # if (slice-starts-with?(word-slice, "#")) break
    # . start/EDX = word-slice->start
    8b/copy                         0/mod/indirect  1/rm32/ECX    .           .             .           2/r32/EDX   .               .                 # copy *ECX to EDX
    # . c/EBX = *start
    31/xor                          3/mod/direct    3/rm32/EBX    .           .             .           3/r32/EBX   .               .                 # clear EBX
    8a/copy-byte                    0/mod/indirect  2/rm32/EDX    .           .             .           3/r32/BL    .               .                 # copy byte at *EDX to BL
    # . if (EBX == '#') break
    81          7/subop/compare     3/mod/direct    3/rm32/EBX    .           .             .           .           .               0x23/imm32/hash   # compare EBX
    74/jump-if-equal  $num-bytes:end/disp8
$num-bytes:check-for-label:
    # if (slice-ends-with?(word-slice, ":")) break
    # . end/EDX = word-slice->end
    8b/copy                         1/mod/*+disp8   1/rm32/ECX    .           .             .           2/r32/EDX   4/disp8         .                 # copy *(ECX+4) to EDX
    # . c/EBX = *(end-1)
    31/xor                          3/mod/direct    3/rm32/EBX    .           .             .           3/r32/EBX   .               .                 # clear EBX
    8a/copy-byte                    1/mod/*+disp8   2/rm32/EDX    .           .             .           3/r32/BL    -1/disp8        .                 # copy byte at *ECX to BL
    # . if (EBX == ':') break
    81          7/subop/compare     3/mod/direct    3/rm32/EBX    .           .             .           .           .               0x3a/imm32/colon  # compare EBX
    74/jump-if-equal  $num-bytes:end/disp8
$num-bytes:check-for-segment-header:
    # if (slice-equal?(word-slice, "==")) break
    # . push result
    50/push-EAX
    # . EAX = slice-equal?(word-slice, "==")
    # . . push args
    68/push  "=="/imm32
    51/push-ECX
    # . . call
    e8/call  slice-equal?/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . if (EAX != 0) break
    3d/compare-EAX-and  0/imm32
    # . restore result now that ZF is set
    58/pop-to-EAX
    75/jump-if-not-equal  $num-bytes:end/disp8
$num-bytes:loop-body:
    # result += compute-width-of-slice(word-slice)
    # . copy result to EDX
    89/copy                         3/mod/direct    2/rm32/EDX    .           .             .           0/r32/EAX   .               .                 # copy EAX to EDX
    # . EAX = compute-width-of-slice(word-slice)
    # . . push args
    51/push-ECX
    # . . call
    e8/call compute-width-of-slice/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # . EAX += result
    01/add                          3/mod/direct    0/rm32/EAX    .           .             .           2/r32/EDX   .               .                 # add EDX to EAX
    e9/jump  $num-bytes:loop/disp32
$num-bytes:end:
    # . reclaim locals
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . restore registers
    5b/pop-to-EBX
    5a/pop-to-EDX
    59/pop-to-ECX
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

test-num-bytes-handles-empty-string:
    # if a line starts with '#', return 0
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # setup
    # . clear-stream(_test-input-stream)
    # . . push args
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  clear-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # . clear-stream(_test-output-stream)
    # . . push args
    68/push  _test-output-stream/imm32
    # . . call
    e8/call  clear-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # no contents in input
    # EAX = num-bytes(_test-input-stream)
    # . . push args
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  num-bytes/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # check-ints-equal(EAX, 0, msg)
    # . . push args
    68/push  "F - test-num-bytes-handles-empty-string"/imm32
    68/push  0/imm32/true
    50/push-EAX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

test-num-bytes-ignores-comments:
    # if a line starts with '#', return 0
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # setup
    # . clear-stream(_test-input-stream)
    # . . push args
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  clear-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # . clear-stream(_test-output-stream)
    # . . push args
    68/push  _test-output-stream/imm32
    # . . call
    e8/call  clear-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # initialize input
    # . write(_test-input-stream, "# abcd")
    # . . push args
    68/push  "# abcd"/imm32
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # EAX = num-bytes(_test-input-stream)
    # . . push args
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  num-bytes/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # check-ints-equal(EAX, 0, msg)
    # . . push args
    68/push  "F - test-num-bytes-ignores-comments"/imm32
    68/push  0/imm32/true
    50/push-EAX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

test-num-bytes-ignores-labels:
    # if the first word ends with ':', return 0
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # setup
    # . clear-stream(_test-input-stream)
    # . . push args
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  clear-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # . clear-stream(_test-output-stream)
    # . . push args
    68/push  _test-output-stream/imm32
    # . . call
    e8/call  clear-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # initialize input
    # . write(_test-input-stream, "ab: # cd")
    # . . push args
    68/push  "ab: # cd"/imm32
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # EAX = num-bytes(_test-input-stream)
    # . . push args
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  num-bytes/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # check-ints-equal(EAX, 0, msg)
    # . . push args
    68/push  "F - test-num-bytes-ignores-labels"/imm32
    68/push  0/imm32/true
    50/push-EAX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

test-num-bytes-ignores-segment-headers:
    # if the first word is '==', return 0
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # setup
    # . clear-stream(_test-input-stream)
    # . . push args
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  clear-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # . clear-stream(_test-output-stream)
    # . . push args
    68/push  _test-output-stream/imm32
    # . . call
    e8/call  clear-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # initialize input
    # . write(_test-input-stream, "== ab cd")
    # . . push args
    68/push  "== ab cd"/imm32
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # EAX = num-bytes(_test-input-stream)
    # . . push args
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  num-bytes/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # check-ints-equal(EAX, 0, msg)
    # . . push args
    68/push  "F - test-num-bytes-ignores-segment-headers"/imm32
    68/push  0/imm32/true
    50/push-EAX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

test-num-bytes-counts-words-by-default:
    # without metadata, count words
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # setup
    # . clear-stream(_test-input-stream)
    # . . push args
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  clear-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # . clear-stream(_test-output-stream)
    # . . push args
    68/push  _test-output-stream/imm32
    # . . call
    e8/call  clear-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # initialize input
    # . write(_test-input-stream, "ab cd ef")
    # . . push args
    68/push  "ab cd ef"/imm32
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # EAX = num-bytes(_test-input-stream)
    # . . push args
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  num-bytes/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # check-ints-equal(EAX, 3, msg)
    # . . push args
    68/push  "F - test-num-bytes-counts-words-by-default"/imm32
    68/push  3/imm32/true
    50/push-EAX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

test-num-bytes-ignores-trailing-comment:
    # trailing comments appropriately ignored
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # setup
    # . clear-stream(_test-input-stream)
    # . . push args
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  clear-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # . clear-stream(_test-output-stream)
    # . . push args
    68/push  _test-output-stream/imm32
    # . . call
    e8/call  clear-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # initialize input
    # . write(_test-input-stream, "ab cd # ef")
    # . . push args
    68/push  "ab cd # ef"/imm32
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # EAX = num-bytes(_test-input-stream)
    # . . push args
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  num-bytes/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # check-ints-equal(EAX, 2, msg)
    # . . push args
    68/push  "F - test-num-bytes-ignores-trailing-comment"/imm32
    68/push  2/imm32/true
    50/push-EAX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

test-num-bytes-handles-imm32:
    # if a word has the /imm32 metadata, count it as 4 bytes
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # setup
    # . clear-stream(_test-input-stream)
    # . . push args
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  clear-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # . clear-stream(_test-output-stream)
    # . . push args
    68/push  _test-output-stream/imm32
    # . . call
    e8/call  clear-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # initialize input
    # . write(_test-input-stream, "ab cd/imm32 ef")
    # . . push args
    68/push  "ab cd/imm32 ef"/imm32
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # EAX = num-bytes(_test-input-stream)
    # . . push args
    68/push  _test-input-stream/imm32
    # . . call
    e8/call  num-bytes/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # check-ints-equal(EAX, 6, msg)
    # . . push args
    68/push  "F - test-num-bytes-handles-imm32"/imm32
    68/push  6/imm32/true
    50/push-EAX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

== data

Segment-size:
  0x1000/imm32/4KB

# This block of bytes gets copied to the start of the output ELF file, with
# some fields filled in.
# http://www.sco.com/developers/gabi/latest/ch4.eheader.html
Elf_header:
  # - length
  0x34/imm32
  # - data
$e_ident:
  7f 45/E 4c/L 46/F
  01/32-bit  01/little-endian  01/file-version  00/no-os-extensions
  00 00 00 00 00 00 00 00  # 8 bytes of padding
$e_type:
  02 00
$e_machine:
  03 00
$e_version:
  1/imm32
Elf_e_entry:
  0x09000000/imm32  # approximate default; must be updated
$e_phoff:
  0x34/imm32  # offset for the 'program header table' containing segment headers
$e_shoff:
  0/imm32  # no sections
$e_flags:
  0/imm32  # unused
$e_ehsize:
  0x34 00
$e_phentsize:
  0x20 00
Elf_e_phnum:
  00 00  # number of segments; must be updated
$e_shentsize:
  00 00  # no sections
$e_shnum:
  00 00
$e_shstrndx:
  00 00

# This block of bytes gets copied after the Elf_header once for each segment.
# Some fields need filling in each time.
# https://docs.oracle.com/cd/E19683-01/816-1386/chapter6-83432/index.html
Elf_program_header_entry:
  # - length
  0x20/imm32
  # - data
$p_type:
  1/imm32/PT_LOAD
Elf_p_offset:
  0/imm32  # byte offset in the file at which a segment begins; must be updated
Elf_p_vaddr:
  0/imm32  # starting address to store the segment at before running the program
Elf_p_paddr:
  0/imm32  # should have same value as Elf_p_vaddr
Elf_p_filesz:
  0/imm32
Elf_p_memsz:
  0/imm32  # should have same value as Elf_p_filesz
Elf_p_flags:
  6/imm32/rw-  # read/write/execute permissions for the segment; must be updated for the code segment
$p_align:
  # we hold this constant; changing it will require adjusting the way we
  # compute the starting address for each segment
  0x1000/imm32

# . . vim:nowrap:textwidth=0