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# Read a series of segments from stdin and concatenate segments with the same
# name on stdout.
#
# Segments are emitted in order of first encounter.
#
# Drop lines that are all comments. They could get misleading after assortment
# because we don't know if they refer to the line above or the line below.
#
# To run (from the subx/ directory):
#   $ ./subx translate *.subx apps/assort.subx -o apps/assort
#   $ cat x
#   == code
#   abc
#   == code
#   def
#   $ cat x  |./subx run apps/assort
#   == code
#   abc
#   def

== 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:  # run tests if necessary, convert stdin if not

    # for debugging: run a single test
#?     e8/call test-convert/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

    # . prolog
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # - 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 structure:
#   row: pair of (address array byte) and (address stream byte)
#   table: (address stream row)

convert:  # in : (address buffered-file), out : (address buffered-file) -> <void>
    # pseudocode:
    #   var table : (address stream) = new-stream(10 rows, 8 bytes each)
    #   read-segments(in, table)
    #   write-segments(out, table)
    #
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # . save registers
    51/push-ECX
    # var table/ECX : (address stream byte) = stream(10 * 8)
    81          5/subop/subtract    3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x50/imm32        # subtract from ESP
    68/push  0x50/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
    # clear-stream(table)
    # . . push args
    51/push-ECX
    # . . call
    e8/call  clear-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
$convert:read:
    # read-segments(in, table)
    # . . push args
    51/push-ECX
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           8/disp8         .                 # push *(EBP+8)
    # . . call
    e8/call  read-segments/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
$convert:write:
    # write-segments(out, table)
    # . . push args
    51/push-ECX
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0xc/disp8       .                 # push *(EBP+12)
    # . . call
    e8/call  write-segments/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
$convert:end:
    # . reclaim locals
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x5c/imm32        # add to ESP
    # . restore registers
    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:
    # . 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 (meta comments in parens)
    #   # comment 1
    #     # comment 2 indented
    #   == code  (new segment)
    #   # comment 3 inside a segment
    #   1
    #                         (empty line)
    #   2 3 # comment 4 inline with other contents
    #   == data  (new segment)
    #   4 5/imm32
    #   == code  (existing segment but non-contiguous with previous iteration)
    #   6 7
    #   8 9  (multiple lines)
    #   == code  (existing segment contiguous with previous iteration)
    #   10 11
    # . write(_test-input-stream, "# comment 1\n")
    # . . push args
    68/push  "# comment 1\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, "  # comment 2 indented\n")
    # . . push args
    68/push  "  # comment 2 indented\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, "== code\n")
    # . . push args
    68/push  "== code\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, "# comment 3 inside a segment\n")
    # . . push args
    68/push  "# comment 3 inside a segment\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, "1\n")
    # . . push args
    68/push  "1\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, "\n")  # empty line
    # . . push args
    68/push  "\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, "2 3 # comment 4 inline with other contents\n")
    # . . push args
    68/push  "2 3 # comment 4 inline with other contents\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\n")
    # . . push args
    68/push  "== data\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, "4 5/imm32\n")
    # . . push args
    68/push  "4 5/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, "== code\n")
    # . . push args
    68/push  "== code\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, "6 7\n")
    # . . push args
    68/push  "6 7\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, "8 9\n")
    # . . push args
    68/push  "8 9\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, "== code\n")
    # . . push args
    68/push  "== code\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, "10 11\n")
    # . . push args
    68/push  "10 11\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 output
    #   == code
    #   1
    #   2 3 # comment 4 inline with other contents
    #   6 7
    #   8 9
    #   10 11
    #   == data
    #   4 5/imm32
#?     # dump output {{{
#?     # . write(2/stderr, "result: ^")
#?     # . . push args
#?     68/push  "result: ^"/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, _test-output-stream)
#?     # . . push args
#?     68/push  _test-output-stream/imm32
#?     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
#?     # }}}
    # . flush(_test-output-buffered-file)
    # . . push args
    68/push  _test-output-buffered-file/imm32
    # . . call
    e8/call  flush/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # . check-next-stream-line-equal(_test-output-stream, "== code", msg)
    # . . push args
    68/push  "F - test-convert/0"/imm32
    68/push  "== code"/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, "1", msg)
    # . . push args
    68/push  "F - test-convert/1"/imm32
    68/push  "1"/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, "2 3 # comment 4 inline with other contents", msg)
    # . . push args
    68/push  "F - test-convert/2"/imm32
    68/push  "2 3 # comment 4 inline with other contents"/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, "6 7", msg)
    # . . push args
    68/push  "F - test-convert/3"/imm32
    68/push  "6 7"/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, "8 9", msg)
    # . . push args
    68/push  "F - test-convert/4"/imm32
    68/push  "8 9"/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, "10 11", msg)
    # . . push args
    68/push  "F - test-convert/5"/imm32
    68/push  "10 11"/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, "== data", msg)
    # . . push args
    68/push  "F - test-convert/6"/imm32
    68/push  "== data"/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, "4 5/imm32", msg)
    # . . push args
    68/push  "F - test-convert/7"/imm32
    68/push  "4 5/imm32"/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

read-segments:  # in : (address buffered-file), table : (address stream row)
    # pseudocode:
    #   var curr-segment = null
    #   var line = new-stream(512, 1)
    #   while true
    #     clear-stream(line)
    #     read-line(in, line)
    #     if (line->write == 0) break             # end of file
    #     var word-slice = next-word(line)
    #     if slice-empty?(word-slice)             # whitespace
    #       continue
    #     if slice-starts-with?(word-slice, "#")  # comment
    #       continue
    #     if slice-equal?(word-slice, "==")
    #       var segment-name = next-word(line)
    #       curr-segment = get-or-insert-segment(table, segment-name, Segment-size)
    #     else
    #       rewind-stream(line)
    #       write-stream(curr-segment, line)  # abort if curr-segment overflows
    #
    # word-slice and segment-name are both slices with disjoint lifetimes, so
    # we'll use the same address for them.
    #
    # registers:
    #   line: ECX
    #   word-slice and segment-name: EDX
    #   segment-name and curr-segment: EBX
    #   word-slice->start: ESI
    #   temporary: EAX
    #
    # . 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
    # var line/ECX : (address stream byte) = stream(512)
    81          5/subop/subtract    3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x200/imm32       # subtract from ESP
    68/push  0x200/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 word-slice/EDX = {0, 0}
    68/push  0/imm32/end
    68/push  0/imm32/curr
    89/copy                         3/mod/direct    2/rm32/EDX    .           .             .           4/r32/ESP   .               .                 # copy ESP to EDX
$read-segments:loop:
    # clear-stream(line)
    # . . push args
    51/push-ECX
    # . . call
    e8/call  clear-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # read-line(in, line)
    # . . push args
    51/push-ECX
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           8/disp8         .                 # push *(EBP+8)
    # . . call
    e8/call  read-line/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
$read-segments:check0:
    # if (line->write == 0) break
    81          7/subop/compare     0/mod/indirect  1/rm32/ECX    .           .             .           .           .               0/imm32           # compare *ECX
    0f 84/jump-if-equal  $read-segments:break/disp32
#?     # dump line {{{
#?     # . write(2/stderr, "LL: ")
#?     # . . push args
#?     68/push  "LL: "/imm32
#?     68/push  2/imm32/stderr
#?     # . . call
#?     e8/call  write/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
#?     # . write-stream(2/stderr, line)
#?     # . . push args
#?     51/push-ECX
#?     68/push  2/imm32/stderr
#?     # . . call
#?     e8/call  write-stream/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
#?     # . write(2/stderr, "$\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
#?     # }}}
    # next-word(line, word-slice)
    # . . push args
    52/push-EDX
    51/push-ECX
    # . . call
    e8/call  next-word/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
$read-segments:check1:
    # if (slice-empty?(word-slice)) continue
    # . EAX = slice-empty?(word-slice)
    # . . push args
    52/push-EDX
    # . . 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) continue
    3d/compare-EAX-and  0/imm32
    0f 85/jump-if-not-equal  $read-segments:loop/disp32
$read-segments:check-for-comment:
    # if (slice-starts-with?(word-slice, "#")) continue
    # . start/ESI = word-slice->start
    8b/copy                         0/mod/indirect  2/rm32/EDX    .           .             .           6/r32/ESI   .               .                 # copy *ECX to ESI
    # . c/EAX = *start
    31/xor                          3/mod/direct    0/rm32/EAX    .           .             .           0/r32/EAX   .               .                 # clear EAX
    8a/copy-byte                    0/mod/indirect  6/rm32/ESI    .           .             .           0/r32/AL    .               .                 # copy byte at *ESI to AL
    # . if (EAX == '#') continue
    3d/compare-EAX-and  0x23/imm32/hash
    0f 84/jump-if-equal  $read-segments:loop/disp32
$read-segments:check-for-segment-header:
#?     # dump word-slice {{{
#?     # . write(2/stderr, "AA: ")
#?     # . . push args
#?     68/push  "AA: "/imm32
#?     68/push  2/imm32/stderr
#?     # . . call
#?     e8/call  write/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
#?     # . clear-stream(Stderr+4)
#?     # . . push args
#?     b8/copy-to-EAX  Stderr/imm32
#?     05/add-to-EAX  4/imm32
#?     50/push-EAX
#?     # . . call
#?     e8/call  clear-stream/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
#?     # . write-slice(Stderr, word-slice)
#?     # . . push args
#?     52/push-EDX
#?     68/push  Stderr/imm32
#?     # . . call
#?     e8/call  write-slice/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
#?     # . flush(Stderr)
#?     # . . push args
#?     68/push  Stderr/imm32
#?     # . . call
#?     e8/call  flush/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
#?     # . write(2/stderr, "$\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
#?     # }}}
    # if slice-equal?(word-slice, "==")
    #   segment-name = next-word(line)
    #   curr-segment = get-or-insert(table, segment-name)
    # . EAX = slice-equal?(word-slice, "==")
    # . . push args
    68/push  "=="/imm32
    52/push-EDX
    # . . 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) goto check3
    81          7/subop/compare     3/mod/direct    0/rm32/EAX    .           .             .           .           .               0/imm32           # compare EAX
    0f 84/jump-if-equal  $read-segments:regular-line/disp32
    # . next-word(line, segment-name)
    # . . push args
    52/push-EDX
    51/push-ECX
    # . . call
    e8/call  next-word/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
#?     # dump segment name {{{
#?     # . write(2/stderr, "AA: ")
#?     # . . push args
#?     68/push  "AA: "/imm32
#?     68/push  2/imm32/stderr
#?     # . . call
#?     e8/call  write/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
#?     # . clear-stream(Stderr+4)
#?     # . . push args
#?     b8/copy-to-EAX  Stderr/imm32
#?     05/add-to-EAX  4/imm32
#?     50/push-EAX
#?     # . . call
#?     e8/call  clear-stream/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
#?     # . write-slice(Stderr, word-slice)
#?     # . . push args
#?     52/push-EDX
#?     68/push  Stderr/imm32
#?     # . . call
#?     e8/call  write-slice/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
#?     # . flush(Stderr)
#?     # . . push args
#?     68/push  Stderr/imm32
#?     # . . call
#?     e8/call  flush/disp32
#?     # . . discard args
#?     81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
#?     # . write(2/stderr, "$\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
#?     # }}}
    # . EAX = get-or-insert-segment(table, segment-name, Segment-size)
    # . . push args
    ff          6/subop/push        0/mod/indirect  5/rm32/.disp32            .             .           .           Segment-size/disp32               # push *Segment-size
    52/push-EDX
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0xc/disp8       .                 # push *(EBP+12)
    # . . call
    e8/call  get-or-insert-segment/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # . curr-segment = EAX
    89/copy                         3/mod/direct    3/rm32/EBX    .           .             .           0/r32/EAX   .               .                 # copy EAX to EBX
    # . continue
    e9/jump  $read-segments:loop/disp32
$read-segments:regular-line:
    # rewind-stream(line)
    # . . push args
    51/push-ECX
    # . . call
    e8/call  rewind-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # write-stream(curr-segment, line)
    # . . push args
    51/push-ECX
    53/push-EBX
    # . . call
    e8/call  write-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # loop
    e9/jump  $read-segments:loop/disp32
$read-segments:break:
$read-segments:end:
    # . reclaim locals
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x214/imm32       # add to ESP
    # . restore registers
    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

write-segments:  # out : (address buffered-file), table : (address stream row)
    # pseudocode:
    #   var curr = table->data
    #   var max = table->data + table->write
    #   while curr < max
    #     name = table[i].name
    #     print out, "== $name\n"
    #     stream = table[i].stream
    #     write-stream-data(out, stream)
    #     curr += 8
    #   flush(out)
    #
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # . save registers
    50/push-EAX
    52/push-EDX
    56/push-ESI
    # ESI = table
    8b/copy                         1/mod/*+disp8   5/rm32/EBP    .           .             .           6/r32/ESI   0xc/disp8       .                 # copy *(EBP+12) to ESI
    # write/EDX = table->write
    8b/copy                         0/mod/indirect  6/rm32/ESI    .           .             .           2/r32/EDX   .               .                 # copy *ESI to EDX
    # curr/ESI = table->data
    81          0/subop/add         3/mod/direct    6/rm32/ESI    .           .             .           .           .               0xc/imm32         # add to EAX
    # max/EDX = curr + write
    01/add                          3/mod/direct    2/rm32/EDX    .           .             .           6/r32/ESI   .               .                 # add ESI to EDX
$write-segments:loop:
    # if (curr >= max) break
    39/compare                      3/mod/direct    6/rm32/ESI    .           .             .           2/r32/EDX   .               .                 # compare ESI with EDX
    7d/jump-if-greater-or-equal  $write-segments:break/disp8
    # name/EAX = table[i].name
    8b/copy                         0/mod/indirect  6/rm32/ESI    .           .             .           0/r32/EAX   .               .                 # copy *ESI to EAX
    # print out, "== $name\n"
    # . write-buffered(out, "== ")
    # . . push args
    68/push  "== "/imm32
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           8/disp8         .                 # push *(EBP+8)
    # . . call
    e8/call  write-buffered/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . write-buffered(out, name)
    # . . push args
    50/push-EAX
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           8/disp8         .                 # push *(EBP+8)
    # . . call
    e8/call  write-buffered/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . write-buffered(out, "\n")
    # . . push args
    68/push  Newline/imm32
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           8/disp8         .                 # push *(EBP+8)
    # . . call
    e8/call  write-buffered/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # stream/EAX = table[i].stream
    8b/copy                         1/mod/*+disp8   6/rm32/ESI    .           .             .           0/r32/EAX   4/disp8         .                 # copy *(ESI+4) to EAX
    # write-stream-data(out, stream)
    # . . push args
    50/push-EAX
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           8/disp8         .                 # push *(EBP+8)
    # . . call
    e8/call  write-stream-data/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
$write-segments:continue:
    # curr += 8
    81          0/subop/add         3/mod/direct    6/rm32/ESI    .           .             .           .           .               8/imm32           # add to ESI
    eb/jump  $write-segments:loop/disp8
$write-segments:break:
    # flush(out)
    # . . push args
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           8/disp8         .                 # push *(EBP+8)
    # . . call
    e8/call  flush/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
$write-segments:end:
    # . restore registers
    5e/pop-to-ESI
    5a/pop-to-EDX
    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

## helpers

# TODO: pass in an allocation descriptor
get-or-insert-segment:  # table : (address stream row), s : (address slice), n : int -> EAX : (address stream)
    # pseudocode:
    #   curr = table->data
    #   max = &table->data[table->write]
    #   while curr < max
    #     if slice-equal?(s, *curr)
    #       return *(curr+4)
    #     curr += 8
    #   if table->write < table->length
    #     *max = slice-to-string(Heap, s)
    #     result = new-stream(Heap, n, 1)
    #     *(max+4) = result
    #     table->write += 8
    #     return result
    #   return 0
    #
    # . 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
    56/push-ESI
    # ESI = table
    8b/copy                         1/mod/*+disp8   5/rm32/EBP    .           .             .           6/r32/ESI   8/disp8         .                 # copy *(EBP+8) to ESI
    # curr/ECX = table->data
    8d/copy-address                 1/mod/*+disp8   6/rm32/ESI    .           .             .           1/r32/ECX   0xc/disp8       .                 # copy ESI+12 to ECX
    # max/EDX = table->data + table->write
    8b/copy                         0/mod/indirect  6/rm32/ESI    .           .             .           2/r32/EDX   .               .                 # copy *ESI to EDX
    8d/copy-address                 0/mod/indirect  4/rm32/sib    1/base/ECX  2/index/EDX   .           2/r32/EDX   .               .                 # copy ECX+EDX to EDX
$get-or-insert-segment:search-loop:
    # if (curr >= max) break
    39/compare                      3/mod/direct    1/rm32/ECX    .           .             .           2/r32/EDX   .               .                 # compare ECX with EDX
    7d/jump-if-greater-or-equal  $get-or-insert-segment:not-found/disp8
    # if (slice-equal?(s, *curr)) return *(curr+4)
    # . EAX = slice-equal?(s, *curr)
    # . . push args
    ff          6/subop/push        0/mod/indirect  1/rm32/ECX    .           .             .           .           .               .                 # push *ECX
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0xc/disp8       .                 # push *(EBP+12)
    # . . 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) return EAX = *(curr+4)
    3d/compare-EAX-and  0/imm32
    74/jump-if-equal  $get-or-insert-segment:mismatch/disp8
    8b/copy                         1/mod/*+disp8   1/rm32/ECX    .           .             .           0/r32/EAX   4/disp8         .                 # copy *(ECX+4) to EAX
    eb/jump  $get-or-insert-segment:end/disp8
$get-or-insert-segment:mismatch:
    # curr += 8
    81          0/subop/add         3/mod/direct    1/rm32/ECX    .           .             .           .           .               8/imm32           # add to ECX
    # loop
    eb/jump  $get-or-insert-segment:search-loop/disp8
$get-or-insert-segment:not-found:
    # result/EAX = 0
    31/xor                          3/mod/direct    0/rm32/EAX    .           .             .           0/r32/EAX   .               .                 # clear EAX
    # if (table->write >= table->length) abort
    8b/copy                         0/mod/indirect  6/rm32/ESI    .           .             .           1/r32/ECX   .               .                 # copy *ESI to ECX
    3b/compare                      1/mod/*+disp8   6/rm32/ESI    .           .             .           1/r32/ECX   8/disp8         .                 # compare ECX with *(ESI+8)
    7d/jump-if-greater-or-equal  $get-or-insert-segment:abort/disp8
    # *max = slice-to-string(Heap, s)
    # . EAX = slice-to-string(Heap, s)
    # . . push args
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0xc/disp8       .                 # push *(EBP+12)
    68/push  Heap/imm32
    # . . call
    e8/call  slice-to-string/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # . *max = EAX
    89/copy                         0/mod/indirect  2/rm32/EDX    .           .             .           0/r32/EAX   .               .                 # copy EAX to *EDX
    # result/EAX = new-stream(Heap, n, 1)
    # . . push args
    68/push  1/imm32
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0x10/disp8      .                 # push *(EBP+16)
    68/push  Heap/imm32
    # . . call
    e8/call  new-stream/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # *(max+4) = result
    89/copy                         1/mod/*+disp8   2/rm32/EDX    .           .             .           0/r32/EAX   4/disp8         .                 # copy EAX to *(EDX+4)
    # table->write += 8
    81          0/subop/add         0/mod/indirect  6/rm32/ESI    .           .             .           .           .               8/imm32           # add to *ESI
$get-or-insert-segment:end:
    # . restore registers
    5e/pop-to-ESI
    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

$get-or-insert-segment:abort:
    # . _write(2/stderr, error)
    # . . push args
    68/push  "get-or-insert-segment: too many segments"/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-get-or-insert-segment:
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # var table/ECX : (address stream byte) = stream(2 * 8)
    81          5/subop/subtract    3/mod/direct    4/rm32/ESP    .           .             .           .           .               0x10/imm32        # subtract from ESP
    68/push  0x10/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
    # EDX : (address slice) = "code"
    68/push  _test-code-segment-end/imm32/end
    68/push  _test-code-segment/imm32/start
    89/copy                         3/mod/direct    2/rm32/EDX    .           .             .           4/r32/ESP   .               .                 # copy ESP to EDX
$test-get-or-insert-segment:first-call:
    # - start with an empty table, insert one segment, verify that it was inserted
    # segment/EAX = get-or-insert-segment(table, "code" slice, 10)
    # . . push args
    68/push  0xa/imm32/segment-length
    52/push-EDX
    51/push-ECX
    # . . call
    e8/call  get-or-insert-segment/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # save segment
    50/push-EAX
    # if (segment != 0) goto next check
    3d/compare-EAX-and  0/imm32
    75/jump-if-not-equal  $test-get-or-insert-segment:check1/disp8
    # fail test
    # . _write(2/stderr, msg)
    # . . push args
    68/push  "F - test-get-or-insert-segment/0\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
    # . increment Num-test-failures
    ff          0/subop/increment   0/mod/indirect  5/rm32/.disp32            .             .           .           Num-test-failures/disp32          # increment *Num-test-failures
    e9/jump  $test-get-or-insert-segment:end/disp32
$test-get-or-insert-segment:check1:
    # check-ints-equal(segment->length, 10, msg)
    # . . push args
    68/push  "F - test-get-or-insert-segment/1"/imm32
    68/push  0xa/imm32/segment-length
    ff          6/subop/push        1/mod/*+disp8   0/rm32/EAX    .           .             .           .           8/disp8         .                 # push *(EAX+8)
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
$test-get-or-insert-segment:check2:
    # check-ints-equal(table->write, rowsize = 8, msg)
    # . . push args
    68/push  "F - test-get-or-insert-segment/2"/imm32
    68/push  8/imm32/row-size
    ff          6/subop/push        0/mod/indirect  1/rm32/ECX    .           .             .           .           .               .                 # push *ECX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # EAX = string-equal?(*table->data, "code")
    # . . push args
    68/push  "code"/imm32
    ff          6/subop/push        1/mod/*+disp8   1/rm32/ECX    .           .             .           .           0xc/disp8       .                 # push *(ECX+12)
    # . . call
    e8/call  string-equal?/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # check-ints-equal(EAX, 1, msg)
    # . . push args
    68/push  "F - test-get-or-insert-segment/3"/imm32
    68/push  1/imm32
    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
$test-get-or-insert-segment:check3:
    # stream/EAX = *(table->data+4)
    8b/copy                         1/mod/*+disp8   1/rm32/ECX    .           .             .           0/r32/EAX   0x10/disp8      .                 # copy *(ECX+16) to EAX
    # check-ints-equal(stream->length, 10, msg)
    # . . push args
    68/push  "F - test-get-or-insert-segment/4"/imm32
    68/push  0xa/imm32/segment-size
    ff          6/subop/push        1/mod/*+disp8   0/rm32/EAX    .           .             .           .           8/disp8         .                 # push *(EAX+8)
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
$test-get-or-insert-segment:second-call:
    # - insert the same segment name again, verify that it was reused
    # segment2/EAX = get-or-insert-segment(table, "code" slice, 8)
    # . . push args
    68/push  8/imm32/segment-length
    52/push-EDX
    51/push-ECX
    # . . call
    e8/call  get-or-insert-segment/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # restore old segment1
    5a/pop-to-EDX
    # check-ints-equal(segment2/EAX, segment1/EDX, msg)
    # . . push args
    68/push  "F - test-get-or-insert-segment/5"/imm32
    52/push-EDX
    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
    # no change to table size
    # . check-ints-equal(table->write, rowsize = 8, msg)
    # . . push args
    68/push  "F - test-get-or-insert-segment/6"/imm32
    68/push  8/imm32/row-size
    ff          6/subop/push        0/mod/indirect  1/rm32/ECX    .           .             .           .           .               .                 # push *ECX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
$test-get-or-insert-segment:third-call:
    # - insert a new segment name, verify that it was inserted
    # EDX : (address slice) = "data"
    c7          0/subop/copy        0/mod/indirect  2/rm32/EDX    .           .             .           .           .               _test-data-segment/imm32  # copy to *EDX
    c7          0/subop/copy        1/mod/*+disp8   2/rm32/EDX    .           .             .           .           4/disp8         _test-data-segment-end/imm32  # copy to *(EDX+4)
    # segment2/EAX = get-or-insert-segment(table, "data" slice, 8)
    # . . push args
    68/push  8/imm32/segment-length
    52/push-EDX
    51/push-ECX
    # . . call
    e8/call  get-or-insert-segment/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
    # table gets a new row
    # . check-ints-equal(table->write, 2 rows = 16, msg)
    # . . push args
    68/push  "F - test-get-or-insert-segment/7"/imm32
    68/push  0x10/imm32/two-rows
    ff          6/subop/push        0/mod/indirect  1/rm32/ECX    .           .             .           .           .               .                 # push *ECX
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
$test-get-or-insert-segment:end:
    # . epilog
    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
    5d/pop-to-EBP
    c3/return

# (re)compute the bounds of the next word in the line
# return empty string on reaching end of file
next-word:  # line : (address stream byte), out : (address slice)
    # . 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
    56/push-ESI
    57/push-EDI
    # ESI = line
    8b/copy                         1/mod/*+disp8   5/rm32/EBP    .           .             .           6/r32/ESI   8/disp8         .                 # copy *(EBP+8) to ESI
    # EDI = out
    8b/copy                         1/mod/*+disp8   5/rm32/EBP    .           .             .           7/r32/EDI   0xc/disp8       .                 # copy *(EBP+12) to EDI
    # skip-chars-matching(line, ' ')
    # . . push args
    68/push  0x20/imm32/space
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           8/disp8         .                 # push *(EBP+8)
    # . . call
    e8/call  skip-chars-matching/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
$next-word:check0:
    # if (line->read >= line->write) clear out and return
    # . EAX = line->read
    8b/copy                         1/mod/*+disp8   6/rm32/ESI    .           .             .           0/r32/EAX   4/disp8         .                 # copy *(ESI+4) to EAX
    # . if (EAX < line->write) goto next check
    3b/compare                      0/mod/indirect  6/rm32/ESI    .           .             .           0/r32/EAX   .               .                 # compare EAX with *ESI
    7c/jump-if-lesser  $next-word:check-for-comment/disp8
    # . return out = {0, 0}
    c7          0/subop/copy        0/mod/direct    7/rm32/EDI    .           .             .           .           .               0/imm32           # copy to *EDI
    c7          0/subop/copy        1/mod/*+disp8   7/rm32/EDI    .           .             .           .           4/disp8         0/imm32           # copy to *(EDI+4)
    eb/jump  $next-word:end/disp8
$next-word:check-for-comment:
    # out->start = &line->data[line->read]
    8b/copy                         1/mod/*+disp8   6/rm32/ESI    .           .             .           1/r32/ECX   4/disp8         .                 # copy *(ESI+4) to ECX
    8d/copy-address                 1/mod/*+disp8   4/rm32/sib    6/base/ESI  1/index/ECX   .           0/r32/EAX   0xc/disp8       .                 # copy ESI+ECX+12 to EAX
    89/copy                         0/mod/indirect  7/rm32/EDI    .           .             .           0/r32/EAX   .               .                 # copy EAX to *EDI
    # if (line->data[line->read] == '#') out->end = &line->data[line->write]), skip rest of stream and return
    # . EAX = line->data[line->read]
    31/xor                          3/mod/direct    0/rm32/EAX    .           .             .           0/r32/EAX   .               .                 # clear EAX
    8a/copy-byte                    1/mod/*+disp8   4/rm32/sib    6/base/ESI  1/index/ECX   .           0/r32/AL    0xc/disp8       .                 # copy byte at *(ESI+ECX+12) to AL
    # . compare
    3d/compare-EAX-and  0x23/imm32/pound
    75/jump-if-not-equal  $next-word:regular-word/disp8
$next-word:comment:
    # . out->end = &line->data[line->write]
    8b/copy                         0/mod/indirect  6/rm32/ESI    .           .             .           0/r32/EAX   .               .                 # copy *ESI to EAX
    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
    89/copy                         1/mod/*+disp8   7/rm32/EDI    .           .             .           0/r32/EAX   4/disp8         .                 # copy EAX to *(EDI+4)
    # . line->read = line->write
    89/copy                         1/mod/*+disp8   6/rm32/ESI    .           .             .           0/r32/EAX   4/disp8         .                 # copy EAX to *(ESI+4)
    # . return
    eb/jump  $next-word:end/disp8
$next-word:regular-word:
    # otherwise skip-chars-not-matching-whitespace(line)  # including trailing newline
    # . . push args
    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           8/disp8         .                 # push *(EBP+8)
    # . . call
    e8/call  skip-chars-not-matching-whitespace/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
    # out->end = &line->data[line->read]
    8b/copy                         1/mod/*+disp8   6/rm32/ESI    .           .             .           1/r32/ECX   4/disp8         .                 # copy *(ESI+4) to ECX
    8d/copy-address                 1/mod/*+disp8   4/rm32/sib    6/base/ESI  1/index/ECX   .           0/r32/EAX   0xc/disp8       .                 # copy ESI+ECX+12 to EAX
    89/copy                         1/mod/*+disp8   7/rm32/EDI    .           .             .           0/r32/EAX   4/disp8         .                 # copy EAX to *(EDI+4)
$next-word:end:
    # . restore registers
    5f/pop-to-EDI
    5e/pop-to-ESI
    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-next-word:
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # setup
    # . clear-stream(_test-stream)
    # . . push args
    68/push  _test-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
    # var slice/ECX = {0, 0}
    68/push  0/imm32/end
    68/push  0/imm32/start
    89/copy                         3/mod/direct    1/rm32/ECX    .           .             .           4/r32/ESP   .               .                 # copy ESP to ECX
    # write(_test-stream, "  ab")
    # . . push args
    68/push  "  ab"/imm32
    68/push  _test-stream/imm32
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # next-word(_test-stream, slice)
    # . . push args
    51/push-ECX
    68/push  _test-stream/imm32
    # . . call
    e8/call  next-word/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # check-ints-equal(slice->start - _test-stream->data, 2, msg)
    # . check-ints-equal(slice->start - _test-stream, 14, msg)
    # . . push args
    68/push  "F - test-next-word: start"/imm32
    68/push  0xe/imm32
    # . . push slice->start - _test-stream
    8b/copy                         0/mod/indirect  1/rm32/ECX    .           .             .           0/r32/EAX   .               .                 # copy *ECX to EAX
    81          5/subop/subtract    3/mod/direct    0/rm32/EAX    .           .             .           .           .               _test-stream/imm32 # subtract from EAX
    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
    # check-ints-equal(slice->end - _test-stream->data, 4, msg)
    # . check-ints-equal(slice->end - _test-stream, 16, msg)
    # . . push args
    68/push  "F - test-next-word: end"/imm32
    68/push  0x10/imm32
    # . . push slice->end - _test-stream
    8b/copy                         1/mod/*+disp8   1/rm32/ECX    .           .             .           0/r32/EAX   4/disp8         .                 # copy *(ECX+4) to EAX
    81          5/subop/subtract    3/mod/direct    0/rm32/EAX    .           .             .           .           .               _test-stream/imm32 # subtract from EAX
    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-next-word-returns-whole-comment:
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # setup
    # . clear-stream(_test-stream)
    # . . push args
    68/push  _test-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
    # var slice/ECX = {0, 0}
    68/push  0/imm32/end
    68/push  0/imm32/start
    89/copy                         3/mod/direct    1/rm32/ECX    .           .             .           4/r32/ESP   .               .                 # copy ESP to ECX
    # write(_test-stream, "  # a")
    # . . push args
    68/push  "  # a"/imm32
    68/push  _test-stream/imm32
    # . . call
    e8/call  write/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # next-word(_test-stream, slice)
    # . . push args
    51/push-ECX
    68/push  _test-stream/imm32
    # . . call
    e8/call  next-word/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # check-ints-equal(slice->start - _test-stream->data, 2, msg)
    # . check-ints-equal(slice->start - _test-stream, 14, msg)
    # . . push args
    68/push  "F - test-next-word-returns-whole-comment: start"/imm32
    68/push  0xe/imm32
    # . . push slice->start - _test-stream
    8b/copy                         0/mod/indirect  1/rm32/ECX    .           .             .           0/r32/EAX   .               .                 # copy *ECX to EAX
    81          5/subop/subtract    3/mod/direct    0/rm32/EAX    .           .             .           .           .               _test-stream/imm32 # subtract from EAX
    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
    # check-ints-equal(slice->end - _test-stream->data, 5, msg)
    # . check-ints-equal(slice->end - _test-stream, 17, msg)
    # . . push args
    68/push  "F - test-next-word-returns-whole-comment: end"/imm32
    68/push  0x11/imm32
    # . . push slice->end - _test-stream
    8b/copy                         1/mod/*+disp8   1/rm32/ECX    .           .             .           0/r32/EAX   4/disp8         .                 # copy *(ECX+4) to EAX
    81          5/subop/subtract    3/mod/direct    0/rm32/EAX    .           .             .           .           .               _test-stream/imm32 # subtract from EAX
    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-next-word-returns-empty-string-on-eof:
    # . prolog
    55/push-EBP
    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
    # setup
    # . clear-stream(_test-stream)
    # . . push args
    68/push  _test-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
    # var slice/ECX = {0, 0}
    68/push  0/imm32/end
    68/push  0/imm32/start
    89/copy                         3/mod/direct    1/rm32/ECX    .           .             .           4/r32/ESP   .               .                 # copy ESP to ECX
    # write nothing to _test-stream
    # next-word(_test-stream, slice)
    # . . push args
    51/push-ECX
    68/push  _test-stream/imm32
    # . . call
    e8/call  next-word/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
    # check-ints-equal(slice->end - slice->start, 0, msg)
    # . . push args
    68/push  "F - test-next-word-returns-empty-string-on-eof"/imm32
    68/push  0/imm32
    # . . push slice->end - slice->start
    8b/copy                         1/mod/*+disp8   1/rm32/ECX    .           .             .           0/r32/EAX   4/disp8         .                 # copy *(ECX+4) to EAX
    2b/subtract                     0/mod/indirect  1/rm32/ECX    .           .             .           0/r32/EAX   .               .                 # subtract *ECX from EAX
    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

_test-code-segment:
  63/c 6f/o 64/d 65/e
_test-code-segment-end:

_test-data-segment:
  64/d 61/a 74/t 61/a
_test-data-segment-end:

Segment-size:
  # TODO: there's currently a tight size limit on segments because we aren't growing the heap
  0x100/imm32/4KB
#?   0x1000/imm32/4KB

# . . vim:nowrap:textwidth=0