linux/apps/ex11.subx


1
2
3
4
5
6
7
8
9
10
11
12
13
14pre { line-height: 125%; }
td.linenos .normal { color: inherit; background-color: transparent; padding-left: 5px; padding-right: 5px; }
span.linenos { color: inherit; background-color: transparent; padding-left: 5px; padding-right: 5px; }
td.linenos .special { color: #000000; background-color: #ffffc0; padding-left: 5px; padding-right: 5px; }
span.linenos.special { color: #000000; background-color: #ffffc0; padding-left: 5px; padding-right: 5px; }
.highlight .hll { background-color: #ffffcc }
.highlight .c { color: #888888 } /* Comment */
.highlight .err { color: #a61717; background-color: #e3d2d2 } /* Error */
.highlight .k { color: #008800; font-weight: bold } /* Keyword */
.highlight .ch { color: #888888 } /* Comment.Hashbang */
.highlight .cm { color: #888888 } /* Comment.Multiline */
.highlight .cp { color: #cc0000; font-weight: bold } /* Comment.Preproc */
.highlight .cpf { color: #888888 } /* Comment.PreprocFile */
.highlight .c1 { color: #888888 } /* Comment.Single */
.highlight .cs { color: #cc0000; font-weight: bold; background-color: #fff0f0 } /* Comment.Special */
.highlight .gd { color: #000000; background-color: #ffdddd } /* Generic.Deleted */
.highlight .ge { font-style: italic } /* Generic.Emph */
.highlight .ges { font-weight: bold; font-style: italic } /* Generic.EmphStrong */
.highlight .gr { color: #aa0000 } /* Generic.Error */
.highlight .gh { color: #333333 } /* Generic.Heading */
.highlight .gi { color: #000000; background-color: #ddffdd } /* Generic.Inserted */
.highlight .go { color: #888888 } /* Generic.Output */
.highlight .gp { color: #555555 } /* Generic.Prompt */
.highlight .gs { font-weight: bold } /* Generic.Strong */
.highlight .gu { color: #666666 } /* Generic.Subheading */
.highlight .gt { color: #aa0000 } /* Generic.Traceback */
.highlight .kc { color: #008800; font-weight: bold } /* Keyword.Constant */
.highlight .kd { color: #008800; font-weight: bold } /* Keyword.Declaration */
.highlight .kn { color: #008800; font-weight: bold } /* Keyword.Namespace */
.highlight .kp { color: #008800 } /* Keyword.Pseudo */
.highlight .kr { color: #008800; font-weight: bold } /* Keyword.Reserved */
.highlight .kt { color: #888888; font-weight: bold } /* Keyword.Type */
.highlight .m { color: #0000DD; font-weight: bold } /* Literal.Number */
.highlight .s { color: #dd2200; background-color: #fff0f0 } /* Literal.String */
.highlight .na { color: #336699 } /* Name.Attribute */
.highlight .nb { color: #003388 } /* Name.Builtin */
.highlight .nc { color: #bb0066; font-weight: bold } /* Name.Class */
.highlight .no { color: #003366; font-weight: bold } /* Name.Constant */
.highlight .nd { color: #555555 } /* Name.Decorator */
.highlight .ne { color: #bb0066; font-weight: bold } /* Name.Exception */
.highlight .nf { color: #0066bb; font-weight: bold } /* Name.Function */
.highlight .nl { color: #336699; font-style: italic } /* Name.Label */
.highlight .nn { color: #bb0066; font-weight: bold } /* Name.Namespace */
.highlight .py { color: #336699; font-weight: bold } /* Name.Property */
.highlight .nt { color: #bb0066; font-weight: bold } /* Name.Tag */
.highlight .nv { color: #336699 } /* Name.Variable */
.highlight .ow { color: #008800 } /* Operator.Word */
.highlight .w { color: #bbbbbb } /* Text.Whitespace */
.highlight .mb { color: #0000DD; font-weight: bold } /* Literal.Number.Bin */
.highlight .mf { color: #0000DD; font-weight: bold } /* Literal.Number.Float */
.highlight .mh { color: #0000DD; font-weight: bold } /* Literal.Number.Hex */
.highlight .mi { color: #0000DD; font-weight: bold } /* Literal.Number.Integer */
.highlight .mo { color: #0000DD; font-weight: bold } /* Literal.Number.Oct */
.highlight .sa { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Affix */
.highlight .sb { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Backtick */
.highlight .sc { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Char */
.highlight .dl { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Delimiter */
.highlight .sd { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Doc */
.highlight .s2 { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Double */
.highlight .se { color: #0044dd; background-color: #fff0f0 } /* Literal.String.Escape */
.highlight .sh { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Heredoc */
.highlight .si { color: #3333bb; background-color: #fff0f0 } /* Literal.String.Interpol */
.highlight .sx { color: #22bb22; background-color: #f0fff0 } /* Literal.String.Other */
.highlight .sr { color: #008800; background-color: #fff0ff } /* Literal.String.Regex */
.highlight .s1 { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Single */
.highlight .ss { color: #aa6600; background-color: #fff0f0 } /* Literal.String.Symbol */
.highlight .bp { color: #003388 } /* Name.Builtin.Pseudo */
.highlight .fm { color: #0066bb; font-weight: bold } /* Name.Function.Magic */
.highlight .vc { color: #336699 } /* Name.Variable.Class */
.highlight .vg { color: #dd7700 } /* Name.Variable.Global */
.highlight .vi { color: #3333bb } /* Name.Variable.Instance */
.highlight .vm { color: #336699 } /* Name.Variable.Magic */
.highlight .il { color: #0000DD; font-weight: bold } /* Literal.Number.Integer.Long */discard """
  line: 8
  errormsg: "public implementation 'tmismatchedvisibility.foo(a: int)' has non-public forward declaration in "
"""

proc foo(a: int): int

proc foo*(a: int): int =
  result = a + a
# Null-terminated vs size-prefixed ascii strings.
#
# By default we create strings with a 4-byte size prefix rather than a null suffix.
# However we still need null-prefixed strings when interacting with the Linux
# kernel in a few places. This layer implements a function for comparing
# a null-terminated 'kernel string' with a size-prefixed 'SubX string'.
#
# To run:
#   $ ./translate_subx 000init.subx apps/ex11.subx
#   $ ./a.elf  # runs a series of tests
#   ......  # all tests pass
#
# (We can't yet run the tests when given a "test" commandline argument,
# because checking for it would require the function being tested! Breakage
# would cause tests to not run, rather than to fail as we'd like.)

== 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 all tests
    e8/call  run-tests/disp32  # 'run-tests' is a function created automatically by SubX. It calls all functions that start with 'test-'.
    # exit(eax)
    89/copy                         3/mod/direct    3/rm32/ebx    .           .             .           0/r32/eax   .               .                 # copy eax to ebx
    e8/call  syscall_exit/disp32

# compare a null-terminated ascii string with a more idiomatic size-prefixed byte array
# reason for the name: the only place we should have null-terminated ascii strings is from commandline args
kernel-string-equal?:  # s: null-terminated ascii string, benchmark: size-prefixed ascii string -> eax: boolean
    # pseudocode:
    #   n = benchmark->size
    #   s1 = s
    #   s2 = benchmark->data
    #   i = 0
    #   while i < n
    #     c1 = *s1
    #     c2 = *s2
    #     if (c1 == 0) return false
    #     if (c1 != c2) return false
    #     ++s1, ++s2, ++i
    #   return *s1 == 0
    #
    # registers:
    #   i: ecx
    #   n: edx
    #   s1: edi
    #   s2: esi
    #   c1: eax
    #   c2: ebx
    #
    # . prologue
    55/push-ebp
    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
    # . save registers
    51/push-ecx
    52/push-edx
    53/push-ebx
    56/push-esi
    57/push-edi
    # s1/edi = s
    8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           7/r32/edi   8/disp8         .                 # copy *(ebp+8) to edi
    # n/edx = benchmark->size
    8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           2/r32/edx   0xc/disp8       .                 # copy *(ebp+12) to edx
    8b/copy                         0/mod/indirect  2/rm32/edx    .           .             .           2/r32/edx   .               .                 # copy *edx to edx
    # s2/esi = benchmark->data
    8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           6/r32/esi   0xc/disp8       .                 # copy *(ebp+12) to esi
    81          0/subop/add         3/mod/direct    6/rm32/esi    .           .             .           .           .               4/imm32           # add to esi
    # i/ecx = c1/eax = c2/ebx = 0
    b9/copy-to-ecx  0/imm32/exit
    b8/copy-to-eax  0/imm32
    bb/copy-to-ebx  0/imm32
$kernel-string-equal?:loop:
    # if (i >= n) break
    39/compare                      3/mod/direct    1/rm32/ecx    .           .             .           2/r32/edx   .               .                 # compare ecx with edx
    7d/jump-if->=  $kernel-string-equal?:break/disp8
    # c1 = *s1
    8a/copy-byte                    0/mod/indirect  7/rm32/edi    .           .             .           0/r32/AL    .               .                 # copy byte at *edi to AL
    # c2 = *s2
    8a/copy-byte                    0/mod/indirect  6/rm32/esi    .           .             .           3/r32/BL    .               .                 # copy byte at *esi to BL
    # if (c1 == 0) return false
    3d/compare-eax-and  0/imm32/null
    74/jump-if-=  $kernel-string-equal?:false/disp8
    # if (c1 != c2) return false
    39/compare                      3/mod/direct    0/rm32/eax    .           .             .           3/r32/ebx   .               .                 # compare eax and ebx
    75/jump-if-!=  $kernel-string-equal?:false/disp8
    # ++i
    41/increment-ecx
    # ++s1
    47/increment-edi
    # ++s2
    46/increment-esi
    eb/jump  $kernel-string-equal?:loop/disp8
$kernel-string-equal?:break:
    # return *s1 == 0
    8a/copy-byte                    0/mod/indirect  7/rm32/edi    .           .             .           0/r32/AL    .               .                 # copy byte at *edi to AL
    3d/compare-eax-and  0/imm32/null
    75/jump-if-!=  $kernel-string-equal?:false/disp8
$kernel-string-equal?:true:
    b8/copy-to-eax  1/imm32
    eb/jump  $kernel-string-equal?:end/disp8
$kernel-string-equal?:false:
    b8/copy-to-eax  0/imm32
$kernel-string-equal?:end:
    # . restore registers
    5f/pop-to-edi
    5e/pop-to-esi
    5b/pop-to-ebx
    5a/pop-to-edx
    59/pop-to-ecx
    # . epilogue
    89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
    5d/pop-to-ebp
    c3/return

# - tests

test-compare-null-kernel-string-with-empty-array:
    # eax = kernel-string-equal?(Null-kernel-string, "")
    # . . push args
    68/push  ""/imm32
    68/push  Null-kernel-string/imm32
    # . . 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-ints-equal(eax, 1, msg)
    # . . push args
    68/push  "F - test-compare-null-kernel-string-with-empty-array"/imm32
    68/push  1/imm32/true
    50/push-eax
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
    c3/return

test-compare-null-kernel-string-with-non-empty-array:
    # eax = kernel-string-equal?(Null-kernel-string, "Abc")
    # . . push args
    68/push  "Abc"/imm32
    68/push  Null-kernel-string/imm32
    # . . 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-ints-equal(eax, 0, msg)
    # . . push args
    68/push  "F - test-compare-null-kernel-string-with-non-empty-array"/imm32
    68/push  0/imm32/false
    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
    c3/return

test-compare-kernel-string-with-equal-array:
    # eax = kernel-string-equal?(_test-Abc-kernel-string, "Abc")
    # . . push args
    68/push  "Abc"/imm32
    68/push  _test-Abc-kernel-string/imm32
    # . . 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-ints-equal(eax, 1, msg)
    # . . push args
    68/push  "F - test-compare-kernel-string-with-equal-array"/imm32
    68/push  1/imm32/true
    50/push-eax
    # . . call
    e8/call  check-ints-equal/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
    c3/return

test-compare-kernel-string-with-inequal-array:
    # eax = kernel-string-equal?(_test-Abc-kernel-string, "Adc")
    # . . push args
    68/push  "Adc"/imm32
    68/push  _test-Abc-kernel-string/imm32
    # . . 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-ints-equal(eax, 0, msg)
    # . . push args
    68/push  "F - test-compare-kernel-string-with-equal-array"/imm32
    68/push  0/imm32/false
    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
    c3/return

test-compare-kernel-string-with-empty-array:
    # eax = kernel-string-equal?(_test-Abc-kernel-string, "")
    # . . push args
    68/push  ""/imm32
    68/push  _test-Abc-kernel-string/imm32
    # . . 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-ints-equal(eax, 0, msg)
    # . . push args
    68/push  "F - test-compare-kernel-string-with-equal-array"/imm32
    68/push  0/imm32/false
    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
    c3/return

test-compare-kernel-string-with-shorter-array:
    # eax = kernel-string-equal?(_test-Abc-kernel-string, "Ab")
    # . . push args
    68/push  "Ab"/imm32
    68/push  _test-Abc-kernel-string/imm32
    # . . 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-ints-equal(eax, 0, msg)
    # . . push args
    68/push  "F - test-compare-kernel-string-with-shorter-array"/imm32
    68/push  0/imm32/false
    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
    c3/return

test-compare-kernel-string-with-longer-array:
    # eax = kernel-string-equal?(_test-Abc-kernel-string, "Abcd")
    # . . push args
    68/push  "Abcd"/imm32
    68/push  _test-Abc-kernel-string/imm32
    # . . 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-ints-equal(eax, 0, msg)
    # . . push args
    68/push  "F - test-compare-kernel-string-with-longer-array"/imm32
    68/push  0/imm32/false
    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
    c3/return

# - helpers

# print msg to stderr if a != b, otherwise print "."
check-ints-equal:  # (a: int, b: int, msg: (addr array byte)) -> boolean
    # . prologue
    55/push-ebp
    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
    # . save registers
    51/push-ecx
    53/push-ebx
    # load args into eax, ebx and ecx
    8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           0/r32/eax   8/disp8         .                 # copy *(ebp+8) to eax
    8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           3/r32/ebx   0xc/disp8       .                 # copy *(ebp+12) to ebx
    # if (eax == b/ebx) print('.') and return
    39/compare                      3/mod/direct    0/rm32/eax    .           .             .           3/r32/ebx   .               .                 # compare eax and ebx
    75/jump-if-unequal  $check-ints-equal:else/disp8
    # . write-stderr('.')
    # . . push args
    68/push  "."/imm32
    # . . call
    e8/call  write-stderr/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
    # . return
    eb/jump  $check-ints-equal:end/disp8
    # otherwise print(msg)
$check-ints-equal:else:
    # copy msg into ecx
    8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           1/r32/ecx   0x10/disp8       .                # copy *(ebp+16) to ecx
    # print(ecx)
    # . . push args
    51/push-ecx
    # . . call
    e8/call  write-stderr/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
    # print newline
    # . . push args
    68/push  Newline/imm32
    # . . call
    e8/call  write-stderr/disp32
    # . . discard args
    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
$check-ints-equal:end:
    # . restore registers
    5b/pop-to-ebx
    59/pop-to-ecx
    # end
    89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
    5d/pop-to-ebp
    c3/return

write-stderr:  # s: (addr array byte) -> <void>
    # . prologue
    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
    # syscall_write(2/stderr, (data) s+4, (size) *s)
    # . . fd = 2 (stderr)
    bb/copy-to-ebx  2/imm32
    # . . x = s+4
    8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           1/r32/ecx   8/disp8         .                 # copy *(ebp+8) to ecx
    81          0/subop/add         3/mod/direct    1/rm32/ecx    .           .             .           .           .               4/imm32           # add to ecx
    # . . size = *s
    8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           2/r32/edx   8/disp8         .                 # copy *(ebp+8) to edx
    8b/copy                         0/mod/indirect  2/rm32/edx    .           .             .           2/r32/edx   .               .                 # copy *edx to edx
    # . . syscall
    e8/call  syscall_write/disp32
    # . restore registers
    5b/pop-to-ebx
    5a/pop-to-edx
    59/pop-to-ecx
    58/pop-to-eax
    # . end
    89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
    5d/pop-to-ebp
    c3/return

== data

Newline:
    # size
    1/imm32
    # data
    0a/newline

# for kernel-string-equal tests
Null-kernel-string:
    00/null

_test-Abc-kernel-string:
    41/A 62/b 63/c 00/null

# . . vim:nowrap:textwidth=0