6612 - reorganize layers

1 files changed, 263 insertions, 0 deletions

diff --git a/105string-equal.subx b/105string-equal.subx
new file mode 100644
index 00000000..d193bb2d
--- /dev/null
+++ b/105string-equal.subx
@@ -0,0 +1,263 @@
+# Comparing 'regular' size-prefixed strings.
+
+== 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 test-compare-equal-strings/disp32
+    e8/call  run-tests/disp32  # 'run-tests' is a function created automatically by SubX. It calls all functions that start with 'test-'.
+    # 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
+    e8/call  syscall_exit/disp32
+
+string-equal?:  # s: (addr array byte), benchmark: (addr array byte) -> eax: boolean
+    # pseudocode:
+    #   if (s->size != benchmark->size) return false
+    #   return string-starts-with?(s, benchmark)
+    #
+    # . prologue
+    55/push-ebp
+    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+    # . save registers
+    51/push-ecx
+    56/push-esi
+    57/push-edi
+    # esi = s
+    8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           6/r32/esi   8/disp8         .                 # copy *(ebp+8) to esi
+    # edi = benchmark
+    8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           7/r32/edi   0xc/disp8       .                 # copy *(ebp+12) to edi
+    # ecx = s->size
+    8b/copy                         0/mod/indirect  6/rm32/esi    .           .             .           1/r32/ecx   .               .                 # copy *esi to ecx
+$string-equal?:sizes:
+    # if (ecx != benchmark->size) return false
+    39/compare                      0/mod/indirect  7/rm32/edi    .           .             .           1/r32/ecx   .               .                 # compare *edi and ecx
+    b8/copy-to-eax  0/imm32/false
+    75/jump-if-!=  $string-equal?:end/disp8
+$string-equal?:contents:
+    # string-starts-with?(s, benchmark)
+    # . . push args
+    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  string-starts-with?/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+$string-equal?:end:
+    # . restore registers
+    5f/pop-to-edi
+    5e/pop-to-esi
+    59/pop-to-ecx
+    # . epilogue
+    89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
+    5d/pop-to-ebp
+    c3/return
+
+string-starts-with?:  # s: (addr array byte), benchmark: (addr array byte) -> eax: boolean
+    # pseudocode:
+    #   if (s->size < benchmark->size) return false
+    #   currs = s->data
+    #   currb = benchmark->data
+    #   maxb = &benchmark->data[benchmark->size]
+    #   while currb < maxb
+    #     c1 = *currs
+    #     c2 = *currb
+    #     if (c1 != c2) return false
+    #     ++currs, ++currb
+    #   return true
+    #
+    # registers:
+    #   currs: esi
+    #   maxs: ecx
+    #   currb: edi
+    #   c1: eax
+    #   c2: ebx
+    #
+    # . prologue
+    55/push-ebp
+    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+    # . save registers
+    51/push-ecx
+    52/push-edx
+    56/push-esi
+    57/push-edi
+    # esi = s
+    8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           6/r32/esi   8/disp8         .                 # copy *(ebp+8) to esi
+    # edi = benchmark
+    8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           7/r32/edi   0xc/disp8       .                 # copy *(ebp+12) to edi
+    # var bsize/ecx: int = benchmark->size
+    8b/copy                         0/mod/indirect  7/rm32/edi    .           .             .           1/r32/ecx   .               .                 # copy *edi to ecx
+$string-starts-with?:sizes:
+    # if (s->size < bsize) return false
+    39/compare                      0/mod/indirect  6/rm32/esi    .           .             .           1/r32/ecx   .               .                 # compare *esi with ecx
+    7c/jump-if-<  $string-starts-with?:false/disp8
+    # var currs/esi: (addr byte) = s->data
+    81          0/subop/add         3/mod/direct    6/rm32/esi    .           .             .           .           .               4/imm32           # add to esi
+    # var currb/edi: (addr byte) = benchmark->data
+    81          0/subop/add         3/mod/direct    7/rm32/edi    .           .             .           .           .               4/imm32           # add to edi
+    # var maxb/ecx: (addr byte) = &benchmark->data[benchmark->size]
+    01/add                          3/mod/direct    1/rm32/ecx    .           .             .           7/r32/edi   .               .                 # add edi to ecx
+    # var c1/eax: byte = 0
+    31/xor                          3/mod/direct    0/rm32/eax    .           .             .           0/r32/eax   .               .                 # clear eax
+    # var c2/edx: byte = 0
+    31/xor                          3/mod/direct    2/rm32/edx    .           .             .           2/r32/edx   .               .                 # clear edx
+$string-starts-with?:loop:
+    # if (currs >= maxs) return true
+    39/compare                      3/mod/direct    7/rm32/edi    .           .             .           1/r32/ecx   .               .                 # compare edi with ecx
+    73/jump-if-addr>=  $string-starts-with?:true/disp8
+    # c1 = *currs
+    8a/copy-byte                    0/mod/indirect  6/rm32/esi    .           .             .           0/r32/AL    .               .                 # copy byte at *esi to AL
+    # c2 = *currb
+    8a/copy-byte                    0/mod/indirect  7/rm32/edi    .           .             .           2/r32/DL    .               .                 # copy byte at *edi to DL
+    # if (c1 != c2) return false
+    39/compare                      3/mod/direct    0/rm32/eax    .           .             .           2/r32/edx   .               .                 # compare eax and edx
+    75/jump-if-!=  $string-starts-with?:false/disp8
+    # ++currs
+    46/increment-esi
+    # ++currb
+    47/increment-edi
+    eb/jump  $string-starts-with?:loop/disp8
+$string-starts-with?:true:
+    b8/copy-to-eax  1/imm32
+    eb/jump  $string-starts-with?:end/disp8
+$string-starts-with?:false:
+    b8/copy-to-eax  0/imm32
+$string-starts-with?:end:
+    # . restore registers
+    5f/pop-to-edi
+    5e/pop-to-esi
+    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-empty-with-empty-string:
+    # eax = string-equal?("", "")
+    # . . push args
+    68/push  ""/imm32
+    68/push  ""/imm32
+    # . . call
+    e8/call  string-equal?/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # check-ints-equal(eax, 1, msg)
+    # . . push args
+    68/push  "F - test-compare-empty-with-empty-string"/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-empty-with-non-empty-string:  # also checks size-mismatch code path
+    # eax = string-equal?("", "Abc")
+    # . . push args
+    68/push  "Abc"/imm32
+    68/push  ""/imm32
+    # . . call
+    e8/call  string-equal?/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # check-ints-equal(eax, 0, msg)
+    # . . push args
+    68/push  "F - test-compare-empty-with-non-empty-string"/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-equal-strings:
+    # eax = string-equal?("Abc", "Abc")
+    # . . push args
+    68/push  "Abc"/imm32
+    68/push  "Abc"/imm32
+    # . . call
+    e8/call  string-equal?/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # check-ints-equal(eax, 1, msg)
+    # . . push args
+    68/push  "F - test-compare-equal-strings"/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-inequal-strings-equal-sizes:
+    # eax = string-equal?("Abc", "Adc")
+    # . . push args
+    68/push  "Adc"/imm32
+    68/push  "Abc"/imm32
+    # . . call
+    e8/call  string-equal?/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    # check-ints-equal(eax, 0, msg)
+    # . . push args
+    68/push  "F - test-compare-inequal-strings-equal-sizes"/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
+
+# helper for later tests
+check-strings-equal:  # s: (addr array byte), expected: (addr array byte), msg: (addr array byte)
+    # . prologue
+    55/push-ebp
+    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+    # . save registers
+    50/push-eax
+    # var eax: boolean = string-equal?(s, expected)
+    # . . push args
+    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  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
+    ff          6/subop/push        1/mod/*+disp8   5/rm32/ebp    .           .             .           .           0x10/disp8      .                 # push *(ebp+16)
+    68/push  1/imm32
+    50/push-eax
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+$check-strings-equal:end:
+    # . restore registers
+    58/pop-to-eax
+    # . epilogue
+    89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
+    5d/pop-to-ebp
+    c3/return
+
+# test the helper
+test-check-strings-equal:
+    # check-strings-equal?("Abc", "Abc")
+    # . . push args
+    68/push  "Abc"/imm32
+    68/push  "Abc"/imm32
+    # . . call
+    e8/call  check-strings-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+    c3/return
+
+# . . vim:nowrap:textwidth=0