5675 - move helpers from subx-common into layers

This undoes 5672 in favor of a new plan:

Layers 000 - 099 are for running without syntax sugar. We use them for
building syntax-sugar passes.

Layers 100 and up are for running with all syntax sugar.

The layers are arranged in approximate order so more phases rely on earlier
layers than later ones.

I plan to not use intermediate syntax sugar (just sigils without calls,
or sigils and calls without braces) anywhere except in the specific passes
implementing them.

1 files changed, 1486 insertions, 0 deletions

diff --git a/apps/hex.subx b/apps/hex.subx
new file mode 100644
index 00000000..e5f13077
--- /dev/null
+++ b/apps/hex.subx
@@ -0,0 +1,1486 @@
+# Read a text file containing whitespace-separated pairs of ascii hex bytes
+# from stdin, and convert them into binary bytes (octets) on stdout. Ignore
+# comments between '#' and newline.
+#
+# To run:
+#   $ ./subx translate init.linux 0*.subx apps/subx-params.subx apps/hex.subx  -o apps/hex
+#   $ echo '80 81 82  # comment'  |./subx run apps/hex  |xxd -
+# Expected output:
+#   00000000: 8081 82
+#
+# Only hex bytes and comments are permitted. Outside of comments all words
+# must be exactly 2 characters long and contain only characters [0-9a-f]. No
+# uppercase hex.
+
+== 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
+    # . prolog
+    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+
+    # initialize heap
+    # . Heap = new-segment(Heap-size)
+    # . . push args
+    68/push  Heap/imm32
+    68/push  Heap-size/imm32
+    # . . call
+    e8/call  new-segment/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+
+    # - if argc > 1 and argv[1] == "test", then return run_tests()
+    # if (argc <= 1) goto interactive
+    81          7/subop/compare     1/mod/*+disp8   5/rm32/ebp    .           .             .           .           0/disp8         1/imm32           # compare *ebp
+    7e/jump-if-lesser-or-equal  $subx-hex-main:interactive/disp8
+    # if (!kernel-string-equal?(argv[1], "test")) goto interactive
+    # . eax = kernel-string-equal?(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
+    # . if (eax == 0) goto interactive
+    3d/compare-eax-and  0/imm32
+    74/jump-if-equal  $subx-hex-main:interactive/disp8
+    # run-tests()
+    e8/call  run-tests/disp32
+    # syscall(exit, *Num-test-failures)
+    8b/copy                         0/mod/indirect  5/rm32/.disp32            .             .           3/r32/ebx   Num-test-failures/disp32          # copy *Num-test-failures to ebx
+    eb/jump  $subx-hex-main:end/disp8
+$subx-hex-main:interactive:
+    # - 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
+    # subx-hex(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  subx-hex/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
+$subx-hex-main:end:
+    b8/copy-to-eax  1/imm32/exit
+    cd/syscall  0x80/imm8
+
+# the main entry point
+subx-hex:  # in : (address buffered-file), out : (address buffered-file), err : (address buffered-file), ed : (address exit-descriptor) -> <void>
+    # pseudocode:
+    #   while true
+    #     eax = convert-next-octet(in, err, ed)
+    #     if (eax == Eof) break
+    #     write-byte-buffered(out, AL)
+    #   flush(out)
+    #
+    # . prolog
+    55/push-ebp
+    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+    # . save registers
+    50/push-eax
+$subx-hex:loop:
+    # eax = convert-next-octet(in, err, ed)
+    # . . 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    .           .             .           .           8/disp8         .                 # push *(ebp+8)
+    # . . call
+    e8/call  convert-next-octet/disp32
+    # . . discard first 2 args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+    # if (eax == Eof) break
+    3d/compare-eax-and  0xffffffff/imm32/Eof
+    74/jump-if-equal  $subx-hex:loop-end/disp8
+    # write-byte-buffered(out, AL)
+    # . . push args
+    50/push-eax
+    ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           0xc/disp8       .                 # push *(ebp+12)
+    # . . call
+    e8/call  write-byte-buffered/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # loop
+    eb/jump  $subx-hex:loop/disp8
+$subx-hex:loop-end:
+    # flush(out)
+    # . . push args
+    ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           0xc/disp8       .                 # push *(ebp+12)
+    # . . call
+    e8/call  flush/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
+$subx-hex:end:
+    # . restore registers
+    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
+
+# read bytes from 'in' until a sequence of two lowercase hex (0-9, a-f) bytes
+# skip spaces and newlines
+# on '#' skip bytes until newline
+# raise an error and abort on all other unexpected bytes
+# return in eax an _octet_ containing the binary value of the two hex characters
+# return Eof on reaching end of file
+convert-next-octet:  # in : (address buffered-file), err : (address buffered-file), ed : (address exit-descriptor) -> byte-or-Eof/eax
+    # pseudocode:
+    #   eax = scan-next-byte(in, err, ed)
+    #   if (eax == Eof) return
+    #   ecx = from-hex-char(eax)
+    #   eax = scan-next-byte(in, err, ed)
+    #   if (eax == Eof) error("partial byte found.")
+    #   eax = from-hex-char(eax)
+    #   eax = (ecx << 4) | eax
+    #   return
+    #
+    # . prolog
+    55/push-ebp
+    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+    # . save registers
+    51/push-ecx
+    # eax = scan-next-byte(in, err, ed)
+    # . . push args
+    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  scan-next-byte/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+    # if (eax == Eof) return
+    3d/compare-eax-and  0xffffffff/imm32/Eof
+    74/jump-if-equal  $convert-next-octet:end/disp8
+    # eax = from-hex-char(eax)
+    e8/call from-hex-char/disp32
+    # ecx = eax
+    89/copy                         3/mod/direct    1/rm32/ecx    .           .             .           0/r32/eax   .               .                 # copy eax to ecx
+    # eax = scan-next-byte(in, err, ed)
+    # . . push args
+    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  scan-next-byte/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+    # if (eax == Eof) error(ed, err, "partial byte found.")
+    3d/compare-eax-and  0xffffffff/imm32/Eof
+    75/jump-if-not-equal  $convert-next-octet:convert/disp8
+    # . error-byte(ed, err, msg, '.')  # reusing error-byte to avoid creating _yet_ another helper
+    # . . push args
+    68/push  0x2e/imm32/period/dummy
+    68/push  "convert-next-octet: partial byte found"/imm32
+    ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           0xc/disp8       .                 # push *(ebp+12)
+    ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           0x10/disp8      .                 # push *(ebp+16)
+    # . . call
+    e8/call  error-byte/disp32  # never returns
+$convert-next-octet:convert:
+    # eax = from-hex-char(eax)
+    e8/call from-hex-char/disp32
+    # eax = (ecx << 4) | eax
+    # . ecx <<= 4
+    c1/shift    4/subop/left        3/mod/direct    1/rm32/ecx    .           .             .           .           .               4/imm8            # shift ecx left by 4 bits
+    # . eax |= ecx
+    09/or                           3/mod/direct    0/rm32/eax    .           .             .           1/r32/ecx   .               .                 # eax = bitwise OR with ecx
+$convert-next-octet:end:
+    # . 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-next-octet:
+    # - check that the first two bytes of the input are assembled into the resulting octet
+    # This test uses exit-descriptors. Use ebp for setting up local variables.
+    55/push-ebp
+    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+    # clear all streams
+    # . 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
+    # . clear-stream(_test-buffered-file+4)
+    # . . push args
+    b8/copy-to-eax  _test-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-error-stream)
+    # . . push args
+    68/push  _test-error-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-error-buffered-file+4)
+    # . . push args
+    b8/copy-to-eax  _test-error-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 '_test-stream' to "abc"
+    # . write(_test-stream, "abc")
+    # . . push args
+    68/push  "abc"/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
+    # initialize exit-descriptor 'ed' for the call to 'convert-next-octet' below
+    # . var ed/ecx : exit-descriptor
+    81          5/subop/subtract    3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # subtract from esp
+    89/copy                         3/mod/direct    1/rm32/ecx    .           .             .           4/r32/esp   .               .                 # copy esp to ecx
+    # . tailor-exit-descriptor(ed, 12)
+    # . . push args
+    68/push  0xc/imm32/nbytes-of-args-for-convert-next-octet
+    51/push-ecx/ed
+    # . . call
+    e8/call  tailor-exit-descriptor/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # eax = convert-next-octet(_test-buffered-file, _test-error-buffered-file, ed)
+    # . . push args
+    51/push-ecx/ed
+    68/push  _test-error-buffered-file/imm32
+    68/push  _test-buffered-file/imm32
+    # . . call
+    e8/call  convert-next-octet/disp32
+    # registers except esp may be clobbered at this point
+    # pop args to convert-next-octet
+    # . . discard first 2 args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # . . restore ed
+    59/pop-to-ecx
+    # check that convert-next-octet didn't abort
+    # . check-ints-equal(ed->value, 0, msg)
+    # . . push args
+    68/push  "F - test-convert-next-octet: unexpected abort"/imm32
+    68/push  0/imm32
+    # . . push ed->value
+    ff          6/subop/push        1/mod/*+disp8   1/rm32/ecx    .           .             .           .           4/disp8         .                 # push *(ecx+4)
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+    # return if abort
+    81          7/subop/compare     1/mod/*+disp8   1/rm32/ecx    .           .             .           .           4/disp8         0/imm32           # compare *(ecx+4)
+    75/jump-if-not-equal  $test-convert-next-octet:end/disp8
+    # check-ints-equal(eax, 0xab, msg)
+    # . . push args
+    68/push  "F - test-convert-next-octet"/imm32
+    68/push  0xab/imm32/ab
+    50/push-eax
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+$test-convert-next-octet:end:
+    # . epilog
+    # don't restore esp from ebp; manually reclaim locals
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    5d/pop-to-ebp
+    c3/return
+
+test-convert-next-octet-handles-Eof:
+    # - check that reaching end of file returns Eof
+    # This test uses exit-descriptors. Use ebp for setting up local variables.
+    55/push-ebp
+    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+    # clear all streams
+    # . 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
+    # . clear-stream(_test-buffered-file+4)
+    # . . push args
+    b8/copy-to-eax  _test-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-error-stream)
+    # . . push args
+    68/push  _test-error-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-error-buffered-file+4)
+    # . . push args
+    b8/copy-to-eax  _test-error-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
+    # don't initialize '_test-stream'
+    # initialize exit-descriptor 'ed' for the call to 'convert-next-octet' below
+    # . var ed/ecx : exit-descriptor
+    81          5/subop/subtract    3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # subtract from esp
+    89/copy                         3/mod/direct    1/rm32/ecx    .           .             .           4/r32/esp   .               .                 # copy esp to ecx
+    # . tailor-exit-descriptor(ed, 12)
+    # . . push args
+    68/push  0xc/imm32/nbytes-of-args-for-convert-next-octet
+    51/push-ecx/ed
+    # . . call
+    e8/call  tailor-exit-descriptor/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # eax = convert-next-octet(_test-buffered-file, _test-error-buffered-file, ed)
+    # . . push args
+    51/push-ecx/ed
+    68/push  _test-error-buffered-file/imm32
+    68/push  _test-buffered-file/imm32
+    # . . call
+    e8/call  convert-next-octet/disp32
+    # registers except esp may be clobbered at this point
+    # pop args to convert-next-octet
+    # . . discard first 2 args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # . . restore ed
+    59/pop-to-ecx
+    # check that convert-next-octet didn't abort
+    # . check-ints-equal(ed->value, 0, msg)
+    # . . push args
+    68/push  "F - test-convert-next-octet: unexpected abort"/imm32
+    68/push  0/imm32
+    # . . push ed->value
+    ff          6/subop/push        1/mod/*+disp8   1/rm32/ecx    .           .             .           .           4/disp8         .                 # push *(ecx+4)
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+    # return if abort
+    81          7/subop/compare     1/mod/*+disp8   1/rm32/ecx    .           .             .           .           4/disp8         0/imm32           # compare *(ecx+4)
+    75/jump-if-not-equal  $test-convert-next-octet-handles-Eof:end/disp8
+    # check-ints-equal(eax, Eof, msg)
+    # . . push args
+    68/push  "F - test-convert-next-octet-handles-Eof"/imm32
+    68/push  0xffffffff/imm32/Eof
+    50/push-eax
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+$test-convert-next-octet-handles-Eof:end:
+    # . epilog
+    # don't restore esp from ebp; manually reclaim locals
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    5d/pop-to-ebp
+    c3/return
+
+test-convert-next-octet-aborts-on-single-hex-byte:
+    # - check that a single unaccompanied hex byte aborts
+    # This test uses exit-descriptors. Use ebp for setting up local variables.
+    55/push-ebp
+    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+    # clear all streams
+    # . 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
+    # . clear-stream(_test-buffered-file+4)
+    # . . push args
+    b8/copy-to-eax  _test-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-error-stream)
+    # . . push args
+    68/push  _test-error-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-error-buffered-file+4)
+    # . . push args
+    b8/copy-to-eax  _test-error-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 '_test-stream' to "a"
+    # . 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
+    # initialize exit-descriptor 'ed' for the call to 'convert-next-octet' below
+    # . var ed/ecx : exit-descriptor
+    81          5/subop/subtract    3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # subtract from esp
+    89/copy                         3/mod/direct    1/rm32/ecx    .           .             .           4/r32/esp   .               .                 # copy esp to ecx
+    # . tailor-exit-descriptor(ed, 12)
+    # . . push args
+    68/push  0xc/imm32/nbytes-of-args-for-convert-next-octet
+    51/push-ecx/ed
+    # . . call
+    e8/call  tailor-exit-descriptor/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # eax = convert-next-octet(_test-buffered-file, _test-error-buffered-file, ed)
+    # . . push args
+    51/push-ecx/ed
+    68/push  _test-error-buffered-file/imm32
+    68/push  _test-buffered-file/imm32
+    # . . call
+    e8/call  convert-next-octet/disp32
+    # registers except esp may be clobbered at this point
+    # pop args to convert-next-octet
+    # . . discard first 2 args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # . . restore ed
+    59/pop-to-ecx
+    # check that convert-next-octet aborted
+    # . check-ints-equal(ed->value, 2, msg)
+    # . . push args
+    68/push  "F - test-convert-next-octet-aborts-on-single-hex-byte: unexpected abort"/imm32
+    68/push  2/imm32
+    # . . push ed->value
+    ff          6/subop/push        1/mod/*+disp8   1/rm32/ecx    .           .             .           .           4/disp8         .                 # push *(ecx+4)
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+$test-convert-next-octet-aborts-on-single-hex-byte:end:
+    # . epilog
+    # don't restore esp from ebp; manually reclaim locals
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    5d/pop-to-ebp
+    c3/return
+
+# read whitespace until a hex byte, and return it
+# return Eof if file ends without finding a hex byte
+# on '#' skip all bytes until newline
+# abort on any other byte
+scan-next-byte:  # in : (address buffered-file), err : (address buffered-file), ed : (address exit-descriptor) -> byte-or-Eof/eax
+    # pseudocode:
+    #   while true
+    #     eax = read-byte-buffered(in)
+    #     if (eax == Eof) return eax
+    #     if (is-hex-digit?(eax)) return eax
+    #     if (eax == ' ' or '\t' or '\n') continue
+    #     if (eax == '#') skip-until-newline(in)
+    #     else error-byte(ed, err, "invalid byte: " eax)
+    #
+    # . prolog
+    55/push-ebp
+    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+    # . save registers
+$scan-next-byte:loop:
+    # eax = read-byte-buffered(in)
+    # . . push args
+    ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           8/disp8         .                 # push *(ebp+8)
+    # . . call
+    e8/call  read-byte-buffered/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
+    # if (eax == Eof) return eax
+    3d/compare-with-eax  0xffffffff/imm32/Eof
+    74/jump-if-equal  $scan-next-byte:end/disp8
+    # if (is-hex-digit?(eax)) return eax
+    # . save eax for now
+    50/push-eax
+    # . is-hex-digit?(eax)
+    # . . push args
+    50/push-eax
+    # . . call
+    e8/call  is-hex-digit?/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
+    # . compare with 'false'
+    3d/compare-with-eax  0/imm32
+    # . restore eax (does not affect flags)
+    58/pop-to-eax
+    # . check whether to return
+    75/jump-if-not-equal  $scan-next-byte:end/disp8
+$scan-next-byte:check1:
+    # if (eax == ' ') continue
+    3d/compare-eax-and  0x20/imm32/space
+    74/jump-if-equal  $scan-next-byte:loop/disp8
+    # if (eax == '\t') continue
+    3d/compare-eax-and  9/imm32/tab
+    74/jump-if-equal  $scan-next-byte:loop/disp8
+    # if (eax == '\n') continue
+    3d/compare-eax-and  0xa/imm32/newline
+    74/jump-if-equal  $scan-next-byte:loop/disp8
+$scan-next-byte:check2:
+    # if (eax == '#') skip-until-newline(in)
+    3d/compare-with-eax  0x23/imm32
+    75/jump-if-not-equal  $scan-next-byte:check3/disp8
+    # . skip-until-newline(in)
+    # . . push args
+    ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           8/disp8         .                 # push *(ebp+8)
+    # . . call
+    e8/call  skip-until-newline/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
+    eb/jump  $scan-next-byte:loop/disp8
+$scan-next-byte:check3:
+    # otherwise error-byte(ed, err, msg, eax)
+    # . . push args
+    50/push-eax
+    68/push  "scan-next-byte: invalid byte"/imm32
+    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    .           .             .           .           0x10/disp8      .                 # push *(ebp+16)
+    # . . call
+    e8/call  error-byte/disp32  # never returns
+$scan-next-byte:end:
+    # . 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-scan-next-byte:
+    # - check that the first byte of the input is returned
+    # This test uses exit-descriptors. Use ebp for setting up local variables.
+    55/push-ebp
+    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+    # clear all streams
+    # . 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
+    # . clear-stream(_test-buffered-file+4)
+    # . . push args
+    b8/copy-to-eax  _test-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-error-stream)
+    # . . push args
+    68/push  _test-error-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-error-buffered-file+4)
+    # . . push args
+    b8/copy-to-eax  _test-error-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 '_test-stream' to "abc"
+    # . write(_test-stream, "abc")
+    # . . push args
+    68/push  "abc"/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
+    # initialize exit-descriptor 'ed' for the call to 'scan-next-byte' below
+    # . var ed/ecx : exit-descriptor
+    81          5/subop/subtract    3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # subtract from esp
+    89/copy                         3/mod/direct    1/rm32/ecx    .           .             .           4/r32/esp   .               .                 # copy esp to ecx
+    # . tailor-exit-descriptor(ed, 12)
+    # . . push args
+    68/push  0xc/imm32/nbytes-of-args-for-scan-next-byte
+    51/push-ecx/ed
+    # . . call
+    e8/call  tailor-exit-descriptor/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # eax = scan-next-byte(_test-buffered-file, _test-error-buffered-file, ed)
+    # . . push args
+    51/push-ecx/ed
+    68/push  _test-error-buffered-file/imm32
+    68/push  _test-buffered-file/imm32
+    # . . call
+    e8/call  scan-next-byte/disp32
+    # registers except esp may be clobbered at this point
+    # pop args to scan-next-byte
+    # . . discard first 2 args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # . . restore ed
+    59/pop-to-ecx
+    # check that scan-next-byte didn't abort
+    # . check-ints-equal(ed->value, 0, msg)
+    # . . push args
+    68/push  "F - test-scan-next-byte: unexpected abort"/imm32
+    68/push  0/imm32
+    # . . push ed->value
+    ff          6/subop/push        1/mod/*+disp8   1/rm32/ecx    .           .             .           .           4/disp8         .                 # push *(ecx+4)
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+    # return if abort
+    81          7/subop/compare     1/mod/*+disp8   1/rm32/ecx    .           .             .           .           4/disp8         0/imm32           # compare *(ecx+4)
+    75/jump-if-not-equal  $test-scan-next-byte:end/disp8
+    # check-ints-equal(eax, 0x61/a, msg)
+    # . . push args
+    68/push  "F - test-scan-next-byte"/imm32
+    68/push  0x61/imm32/a
+    50/push-eax
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+$test-scan-next-byte:end:
+    # . epilog
+    # don't restore esp from ebp; manually reclaim locals
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    5d/pop-to-ebp
+    c3/return
+
+test-scan-next-byte-skips-whitespace:
+    # - check that the first byte after whitespace is returned
+    # This test uses exit-descriptors. Use ebp for setting up local variables.
+    55/push-ebp
+    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+    # clear all streams
+    # . 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
+    # . clear-stream(_test-buffered-file+4)
+    # . . push args
+    b8/copy-to-eax  _test-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-error-stream)
+    # . . push args
+    68/push  _test-error-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-error-buffered-file+4)
+    # . . push args
+    b8/copy-to-eax  _test-error-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 '_test-stream' to input with leading whitespace
+    # . write(_test-stream, text)
+    # . . push args
+    68/push  "  abc"/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
+    # initialize exit-descriptor 'ed' for the call to 'scan-next-byte' below
+    # . var ed/ecx : exit-descriptor
+    81          5/subop/subtract    3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # subtract from esp
+    89/copy                         3/mod/direct    1/rm32/ecx    .           .             .           4/r32/esp   .               .                 # copy esp to ecx
+    # . tailor-exit-descriptor(ed, 12)
+    # . . push args
+    68/push  0xc/imm32/nbytes-of-args-for-scan-next-byte
+    51/push-ecx/ed
+    # . . call
+    e8/call  tailor-exit-descriptor/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # eax = scan-next-byte(_test-buffered-file, _test-error-buffered-file, ed)
+    # . . push args
+    51/push-ecx/ed
+    68/push  _test-error-buffered-file/imm32
+    68/push  _test-buffered-file/imm32
+    # . . call
+    e8/call  scan-next-byte/disp32
+    # registers except esp may be clobbered at this point
+    # pop args to scan-next-byte
+    # . . discard first 2 args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # . . restore ed
+    59/pop-to-ecx
+    # check that scan-next-byte didn't abort
+    # . check-ints-equal(ed->value, 0, msg)
+    # . . push args
+    68/push  "F - test-scan-next-byte-skips-whitespace: unexpected abort"/imm32
+    68/push  0/imm32
+    # . . push ed->value
+    ff          6/subop/push        1/mod/*+disp8   1/rm32/ecx    .           .             .           .           4/disp8         .                 # push *(ecx+4)
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+    # return if abort
+    81          7/subop/compare     1/mod/*+disp8   1/rm32/ecx    .           .             .           .           4/disp8         0/imm32           # compare *(ecx+4)
+    75/jump-if-not-equal  $test-scan-next-byte-skips-whitespace:end/disp8
+    # check-ints-equal(eax, 0x61/a, msg)
+    # . . push args
+    68/push  "F - test-scan-next-byte-skips-whitespace"/imm32
+    68/push  0x61/imm32/a
+    50/push-eax
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+$test-scan-next-byte-skips-whitespace:end:
+    # . epilog
+    # don't restore esp from ebp; manually reclaim locals
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    5d/pop-to-ebp
+    c3/return
+
+test-scan-next-byte-skips-comment:
+    # - check that the first byte after a comment (and newline) is returned
+    # This test uses exit-descriptors. Use ebp for setting up local variables.
+    55/push-ebp
+    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+    # clear all streams
+    # . 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
+    # . clear-stream(_test-buffered-file+4)
+    # . . push args
+    b8/copy-to-eax  _test-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-error-stream)
+    # . . push args
+    68/push  _test-error-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-error-buffered-file+4)
+    # . . push args
+    b8/copy-to-eax  _test-error-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 '_test-stream' to input with leading comment
+    # . write(_test-stream, comment)
+    # . . push args
+    68/push  "#x\n"/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
+    # . write(_test-stream, real text)
+    # . . 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
+    # initialize exit-descriptor 'ed' for the call to 'scan-next-byte' below
+    # . var ed/ecx : exit-descriptor
+    81          5/subop/subtract    3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # subtract from esp
+    89/copy                         3/mod/direct    1/rm32/ecx    .           .             .           4/r32/esp   .               .                 # copy esp to ecx
+    # . tailor-exit-descriptor(ed, 12)
+    # . . push args
+    68/push  0xc/imm32/nbytes-of-args-for-scan-next-byte
+    51/push-ecx/ed
+    # . . call
+    e8/call  tailor-exit-descriptor/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # eax = scan-next-byte(_test-buffered-file, _test-error-buffered-file, ed)
+    # . . push args
+    51/push-ecx/ed
+    68/push  _test-error-buffered-file/imm32
+    68/push  _test-buffered-file/imm32
+    # . . call
+    e8/call  scan-next-byte/disp32
+    # registers except esp may be clobbered at this point
+    # pop args to scan-next-byte
+    # . . discard first 2 args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # . . restore ed
+    59/pop-to-ecx
+    # check that scan-next-byte didn't abort
+    # . check-ints-equal(ed->value, 0, msg)
+    # . . push args
+    68/push  "F - test-scan-next-byte-skips-comment: unexpected abort"/imm32
+    68/push  0/imm32
+    # . . push ed->value
+    ff          6/subop/push        1/mod/*+disp8   1/rm32/ecx    .           .             .           .           4/disp8         .                 # push *(ecx+4)
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+    # return if abort
+    81          7/subop/compare     1/mod/*+disp8   1/rm32/ecx    .           .             .           .           4/disp8         0/imm32           # compare *(ecx+4)
+    75/jump-if-not-equal  $test-scan-next-byte-skips-comment:end/disp8
+    # check-ints-equal(eax, 0x61/a, msg)
+    # . . push args
+    68/push  "F - test-scan-next-byte-skips-comment"/imm32
+    68/push  0x61/imm32/a
+    50/push-eax
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+$test-scan-next-byte-skips-comment:end:
+    # . epilog
+    # don't restore esp from ebp; manually reclaim locals
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    5d/pop-to-ebp
+    c3/return
+
+test-scan-next-byte-skips-comment-and-whitespace:
+    # - check that the first byte after a comment and any further whitespace is returned
+    # This test uses exit-descriptors. Use ebp for setting up local variables.
+    55/push-ebp
+    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+    # clear all streams
+    # . 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
+    # . clear-stream(_test-buffered-file+4)
+    # . . push args
+    b8/copy-to-eax  _test-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-error-stream)
+    # . . push args
+    68/push  _test-error-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-error-buffered-file+4)
+    # . . push args
+    b8/copy-to-eax  _test-error-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 '_test-stream' to input with leading comment and more whitespace after newline
+    # . write(_test-stream, comment)
+    # . . push args
+    68/push  "#x\n"/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
+    # . write(_test-stream, real text)
+    # . . 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
+    # initialize exit-descriptor 'ed' for the call to 'scan-next-byte' below
+    # . var ed/ecx : exit-descriptor
+    81          5/subop/subtract    3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # subtract from esp
+    89/copy                         3/mod/direct    1/rm32/ecx    .           .             .           4/r32/esp   .               .                 # copy esp to ecx
+    # . tailor-exit-descriptor(ed, 12)
+    # . . push args
+    68/push  0xc/imm32/nbytes-of-args-for-scan-next-byte
+    51/push-ecx/ed
+    # . . call
+    e8/call  tailor-exit-descriptor/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # eax = scan-next-byte(_test-buffered-file, _test-error-buffered-file, ed)
+    # . . push args
+    51/push-ecx/ed
+    68/push  _test-error-buffered-file/imm32
+    68/push  _test-buffered-file/imm32
+    # . . call
+    e8/call  scan-next-byte/disp32
+    # registers except esp may be clobbered at this point
+    # pop args to scan-next-byte
+    # . . discard first 2 args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # . . restore ed
+    59/pop-to-ecx
+    # check that scan-next-byte didn't abort
+    # . check-ints-equal(ed->value, 0, msg)
+    # . . push args
+    68/push  "F - test-scan-next-byte-skips-comment-and-whitespace: unexpected abort"/imm32
+    68/push  0/imm32
+    # . . push ed->value
+    ff          6/subop/push        1/mod/*+disp8   1/rm32/ecx    .           .             .           .           4/disp8         .                 # push *(ecx+4)
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+    # return if abort
+    81          7/subop/compare     1/mod/*+disp8   1/rm32/ecx    .           .             .           .           4/disp8         0/imm32           # compare *(ecx+4)
+    75/jump-if-not-equal  $test-scan-next-byte-skips-comment-and-whitespace:end/disp8
+    # check-ints-equal(eax, 0x61/a, msg)
+    # . . push args
+    68/push  "F - test-scan-next-byte-skips-comment-and-whitespace"/imm32
+    68/push  0x61/imm32/a
+    50/push-eax
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+$test-scan-next-byte-skips-comment-and-whitespace:end:
+    # . epilog
+    # don't restore esp from ebp; manually reclaim locals
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    5d/pop-to-ebp
+    c3/return
+
+test-scan-next-byte-skips-whitespace-and-comment:
+    # - check that the first byte after any whitespace and comments is returned
+    # This test uses exit-descriptors. Use ebp for setting up local variables.
+    55/push-ebp
+    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+    # clear all streams
+    # . 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
+    # . clear-stream(_test-buffered-file+4)
+    # . . push args
+    b8/copy-to-eax  _test-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-error-stream)
+    # . . push args
+    68/push  _test-error-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-error-buffered-file+4)
+    # . . push args
+    b8/copy-to-eax  _test-error-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 '_test-stream' to input with leading whitespace and comment
+    # . write(_test-stream, comment)
+    # . . push args
+    68/push  " #x\n"/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
+    # . write(_test-stream, real text)
+    # . . 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
+    # initialize exit-descriptor 'ed' for the call to 'scan-next-byte' below
+    # . var ed/ecx : exit-descriptor
+    81          5/subop/subtract    3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # subtract from esp
+    89/copy                         3/mod/direct    1/rm32/ecx    .           .             .           4/r32/esp   .               .                 # copy esp to ecx
+    # . tailor-exit-descriptor(ed, 12)
+    # . . push args
+    68/push  0xc/imm32/nbytes-of-args-for-scan-next-byte
+    51/push-ecx/ed
+    # . . call
+    e8/call  tailor-exit-descriptor/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # eax = scan-next-byte(_test-buffered-file, _test-error-buffered-file, ed)
+    # . . push args
+    51/push-ecx/ed
+    68/push  _test-error-buffered-file/imm32
+    68/push  _test-buffered-file/imm32
+    # . . call
+    e8/call  scan-next-byte/disp32
+    # registers except esp may be clobbered at this point
+    # pop args to scan-next-byte
+    # . . discard first 2 args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # . . restore ed
+    59/pop-to-ecx
+    # check that scan-next-byte didn't abort
+    # . check-ints-equal(ed->value, 0, msg)
+    # . . push args
+    68/push  "F - test-scan-next-byte-skips-whitespace-and-comment: unexpected abort"/imm32
+    68/push  0/imm32
+    # . . push ed->value
+    ff          6/subop/push        1/mod/*+disp8   1/rm32/ecx    .           .             .           .           4/disp8         .                 # push *(ecx+4)
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+    # return if abort
+    81          7/subop/compare     1/mod/*+disp8   1/rm32/ecx    .           .             .           .           4/disp8         0/imm32           # compare *(ecx+4)
+    75/jump-if-not-equal  $test-scan-next-byte-skips-whitespace-and-comment:end/disp8
+    # check-ints-equal(eax, 0x61/a, msg)
+    # . . push args
+    68/push  "F - test-scan-next-byte-skips-whitespace-and-comment"/imm32
+    68/push  0x61/imm32/a
+    50/push-eax
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+$test-scan-next-byte-skips-whitespace-and-comment:end:
+    # . epilog
+    # don't restore esp from ebp; manually reclaim locals
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    5d/pop-to-ebp
+    c3/return
+
+test-scan-next-byte-reads-final-byte:
+    # - check that the final byte in input is returned
+    # This test uses exit-descriptors. Use ebp for setting up local variables.
+    55/push-ebp
+    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+    # clear all streams
+    # . 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
+    # . clear-stream(_test-buffered-file+4)
+    # . . push args
+    b8/copy-to-eax  _test-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-error-stream)
+    # . . push args
+    68/push  _test-error-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-error-buffered-file+4)
+    # . . push args
+    b8/copy-to-eax  _test-error-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 '_test-stream' to input with single character
+    # . write(_test-stream, character)
+    # . . 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
+    # initialize exit-descriptor 'ed' for the call to 'scan-next-byte' below
+    # . var ed/ecx : exit-descriptor
+    81          5/subop/subtract    3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # subtract from esp
+    89/copy                         3/mod/direct    1/rm32/ecx    .           .             .           4/r32/esp   .               .                 # copy esp to ecx
+    # . tailor-exit-descriptor(ed, 12)
+    # . . push args
+    68/push  0xc/imm32/nbytes-of-args-for-scan-next-byte
+    51/push-ecx/ed
+    # . . call
+    e8/call  tailor-exit-descriptor/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # eax = scan-next-byte(_test-buffered-file, _test-error-buffered-file, ed)
+    # . . push args
+    51/push-ecx/ed
+    68/push  _test-error-buffered-file/imm32
+    68/push  _test-buffered-file/imm32
+    # . . call
+    e8/call  scan-next-byte/disp32
+    # registers except esp may be clobbered at this point
+    # pop args to scan-next-byte
+    # . . discard first 2 args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # . . restore ed
+    59/pop-to-ecx
+    # check that scan-next-byte didn't abort
+    # . check-ints-equal(ed->value, 0, msg)
+    # . . push args
+    68/push  "F - test-scan-next-byte-reads-final-byte: unexpected abort"/imm32
+    68/push  0/imm32
+    # . . push ed->value
+    ff          6/subop/push        1/mod/*+disp8   1/rm32/ecx    .           .             .           .           4/disp8         .                 # push *(ecx+4)
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+    # return if abort
+    81          7/subop/compare     1/mod/*+disp8   1/rm32/ecx    .           .             .           .           4/disp8         0/imm32           # compare *(ecx+4)
+    75/jump-if-not-equal  $test-scan-next-byte-reads-final-byte:end/disp8
+    # check-ints-equal(eax, 0x61/a, msg)
+    # . . push args
+    68/push  "F - test-scan-next-byte-reads-final-byte"/imm32
+    68/push  0x61/imm32/a
+    50/push-eax
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+$test-scan-next-byte-reads-final-byte:end:
+    # . epilog
+    # don't restore esp from ebp; manually reclaim locals
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    5d/pop-to-ebp
+    c3/return
+
+test-scan-next-byte-handles-Eof:
+    # - check that the right sentinel value is returned when there's no data remaining to be read
+    # This test uses exit-descriptors. Use ebp for setting up local variables.
+    55/push-ebp
+    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+    # clear all streams
+    # . 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
+    # . clear-stream(_test-buffered-file+4)
+    # . . push args
+    b8/copy-to-eax  _test-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-error-stream)
+    # . . push args
+    68/push  _test-error-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-error-buffered-file+4)
+    # . . push args
+    b8/copy-to-eax  _test-error-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
+    # leave '_test-stream' empty
+    # initialize exit-descriptor 'ed' for the call to 'scan-next-byte' below
+    # . var ed/ecx : exit-descriptor
+    81          5/subop/subtract    3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # subtract from esp
+    89/copy                         3/mod/direct    1/rm32/ecx    .           .             .           4/r32/esp   .               .                 # copy esp to ecx
+    # . tailor-exit-descriptor(ed, 12)
+    # . . push args
+    68/push  0xc/imm32/nbytes-of-args-for-scan-next-byte
+    51/push-ecx/ed
+    # . . call
+    e8/call  tailor-exit-descriptor/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # eax = scan-next-byte(_test-buffered-file, _test-error-buffered-file, ed)
+    # . . push args
+    51/push-ecx/ed
+    68/push  _test-error-buffered-file/imm32
+    68/push  _test-buffered-file/imm32
+    # . . call
+    e8/call  scan-next-byte/disp32
+    # registers except esp may be clobbered at this point
+    # pop args to scan-next-byte
+    # . . discard first 2 args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # . . restore ed
+    59/pop-to-ecx
+    # check that scan-next-byte didn't abort
+    # . check-ints-equal(ed->value, 0, msg)
+    # . . push args
+    68/push  "F - test-scan-next-byte-handles-Eof: unexpected abort"/imm32
+    68/push  0/imm32
+    # . . push ed->value
+    ff          6/subop/push        1/mod/*+disp8   1/rm32/ecx    .           .             .           .           4/disp8         .                 # push *(ecx+4)
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+    # return if abort
+    81          7/subop/compare     1/mod/*+disp8   1/rm32/ecx    .           .             .           .           4/disp8         0/imm32           # compare *(ecx+4)
+    75/jump-if-not-equal  $test-scan-next-byte-handles-Eof:end/disp8
+    # check-ints-equal(eax, Eof, msg)
+    # . . push args
+    68/push  "F - test-scan-next-byte-handles-Eof"/imm32
+    68/push  0xffffffff/imm32/Eof
+    50/push-eax
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+$test-scan-next-byte-handles-Eof:end:
+    # . epilog
+    # don't restore esp from ebp; manually reclaim locals
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    5d/pop-to-ebp
+    c3/return
+
+test-scan-next-byte-aborts-on-invalid-byte:
+    # - check that the a bad byte immediately aborts
+    # This test uses exit-descriptors. Use ebp for setting up local variables.
+    55/push-ebp
+    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+    # clear all streams
+    # . 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
+    # . clear-stream(_test-buffered-file+4)
+    # . . push args
+    b8/copy-to-eax  _test-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-error-stream)
+    # . . push args
+    68/push  _test-error-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-error-buffered-file+4)
+    # . . push args
+    b8/copy-to-eax  _test-error-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 '_test-stream' to "x"
+    # . write(_test-stream, "x")
+    # . . push args
+    68/push  "x"/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
+    # initialize exit-descriptor 'ed' for the call to 'scan-next-byte' below
+    # . var ed/ecx : exit-descriptor
+    81          5/subop/subtract    3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # subtract from esp
+    89/copy                         3/mod/direct    1/rm32/ecx    .           .             .           4/r32/esp   .               .                 # copy esp to ecx
+    # . tailor-exit-descriptor(ed, 12)
+    # . . push args
+    68/push  0xc/imm32/nbytes-of-args-for-scan-next-byte
+    51/push-ecx/ed
+    # . . call
+    e8/call  tailor-exit-descriptor/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # eax = scan-next-byte(_test-buffered-file, _test-error-buffered-file, ed)
+    # . . push args
+    51/push-ecx/ed
+    68/push  _test-error-buffered-file/imm32
+    68/push  _test-buffered-file/imm32
+    # . . call
+    e8/call  scan-next-byte/disp32
+    # registers except esp may be clobbered at this point
+    # pop args to scan-next-byte
+    # . . discard first 2 args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # . . restore ed
+    59/pop-to-ecx
+    # check that scan-next-byte aborted
+    # . check-ints-equal(ed->value, 2, msg)
+    # . . push args
+    68/push  "F - test-scan-next-byte-aborts-on-invalid-byte"/imm32
+    68/push  2/imm32
+    # . . push ed->value
+    ff          6/subop/push        1/mod/*+disp8   1/rm32/ecx    .           .             .           .           4/disp8         .                 # push *(ecx+4)
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+$test-scan-next-byte-aborts-on-invalid-byte:end:
+    # . epilog
+    # don't restore esp from ebp; manually reclaim locals
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    5d/pop-to-ebp
+    c3/return
+
+skip-until-newline:  # in : (address buffered-file) -> <void>
+    # pseudocode:
+    #   push eax
+    #   while true
+    #     eax = read-byte-buffered(in)
+    #     if (eax == Eof) break
+    #     if (eax == 0x0a) break
+    #   pop eax
+    # . prolog
+    55/push-ebp
+    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+    # . save registers
+    50/push-eax
+$skip-until-newline:loop:
+    # . eax = read-byte-buffered(in)
+    # . . push args
+    ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           8/disp8         .                 # push *(ebp+8)
+    # . . call
+    e8/call  read-byte-buffered/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
+    # . if (eax == Eof) break
+    3d/compare-eax-and  0xffffffff/imm32/Eof
+    74/jump-if-equal  $skip-until-newline:end/disp8
+    # . if (eax != 0xa/newline) loop
+    3d/compare-eax-and  0xa/imm32/newline
+    75/jump-if-not-equal  $skip-until-newline:loop/disp8
+$skip-until-newline:end:
+    # . restore registers
+    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-skip-until-newline:
+    # - check that the read pointer points after the newline
+    # 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
+    # . clear-stream(_test-buffered-file+4)
+    # . . push args
+    b8/copy-to-eax  _test-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 '_test-stream' to "abc\nde"
+    # . write(_test-stream, "abc")
+    # . . push args
+    68/push  "abc\n"/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
+    # . write(_test-stream, "de")
+    # . . push args
+    68/push  "de"/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
+    # skip-until-newline(_test-buffered-file)
+    # . . push args
+    68/push  _test-buffered-file/imm32
+    # . . call
+    e8/call  skip-until-newline/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
+    # check-ints-equal(_test-buffered-file->read, 4, msg)
+    # . . push args
+    68/push  "F - test-skip-until-newline"/imm32
+    68/push  4/imm32
+    b8/copy-to-eax  _test-buffered-file/imm32
+    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
+    # . end
+    c3/return
+
+# . . vim:nowrap:textwidth=0