diff options
Diffstat (limited to 'subx/examples/ex10.subx')
| -rw-r--r-- | subx/examples/ex10.subx | 77 |
1 files changed, 76 insertions, 1 deletions
diff --git a/subx/examples/ex10.subx b/subx/examples/ex10.subx index 321cee64..1a426e28 100644 --- a/subx/examples/ex10.subx +++ b/subx/examples/ex10.subx @@ -26,9 +26,11 @@ # push args 50/push . . . . . . . . # push EAX 53/push . . . . . . . . # push EBX +#? e8/call write_argv_3/disp32 # call - e8/call argv_equal/disp32 + e8/call argv_equal/disp32 # exit(EAX) +$exit: 89/copy 3/mod/direct 3/rm32/EBX . . . 0/r32/EAX . . # copy EAX to EBX b8/copy . . . . . . . 1/imm32 # copy 1 to EAX cd/syscall 0x80/imm8 @@ -39,11 +41,18 @@ argv_equal: # (s1, s2) : null-terminated ascii strings -> EAX : boolean # initialize s1 (ECX) and s2 (EDX) 8b/copy 1/mod/*+disp8 4/rm32/sib 4/base/ESP 4/index/none . 1/r32/ECX 8/disp8 . # copy *(ESP+8) to ECX 8b/copy 1/mod/*+disp8 4/rm32/sib 4/base/ESP 4/index/none . 2/r32/EDX 4/disp8 . # copy *(ESP+4) to EDX +#? # i/ESI = 0 +#? be/copy 0/imm32 # copy 0 to ESI # while (true) $argv_loop: # c1/EAX, c2/EBX = *s1, *s2 + b8/copy 0/imm32 # clear EAX 8a/copy 0/mod/indirect 1/rm32/ECX . . . 0/r32/EAX . . # copy byte at *ECX to lower byte of EAX + bb/copy 0/imm32 # clear EBX 8a/copy 0/mod/indirect 2/rm32/EDX . . . 3/r32/EBX . . # copy byte at *EDX to lower byte of EBX +#? # if (i == _) exit(EAX) +#? 81 7/subop 3/mod/direct 6/rm32/ESI 3/imm32 # compare ESI with _ +#? 74/jump-if-equal $exit/disp8 # if (c1 == 0) break 3d/compare . . . . . . . 0/imm32 # compare EAX with 0 74/jump-if-equal $argv_break/disp8 @@ -53,7 +62,15 @@ $argv_loop: # ++s1, ++s2 41/inc-ECX 42/inc-EDX +#? # ++i +#? 46/inc-ESI # end while +#? 68/push X/imm32 +#? e8/call write_stderr/disp32 +#? 81 0/subop/add 3/mod/direct 4/rm32/ESP 4/imm32 # add 4 to ESP +#? 51/push . . . . . . . . # push ECX +#? e8/call write_argv_3/disp32 +#? 81 0/subop/add 3/mod/direct 4/rm32/ESP 4/imm32 # add 4 to ESP eb/jump $argv_loop/disp8 $argv_break: # if (c2 == 0) return true @@ -65,3 +82,61 @@ $argv_break: $argv_fail: b8/copy . . . . . . . 0/imm32 # copy 0 to EAX c3/return + +write_stderr: # s : (address array byte) -> <void> + # save registers + 50/push . . . . . . . . # push EAX + 51/push . . . . . . . . # push ECX + 52/push . . . . . . . . # push EDX + 53/push . . . . . . . . # push EBX + # write(2/stderr, (data) s+4, (size) *s) + # fd = 2 (stderr) + bb/copy . . . . . . . 2/imm32 # copy 2 to EBX + # x = s+4 + 8b/copy 1/mod/*+disp8 4/rm32/SIB 4/base/ESP 4/index/none . 1/r32/ECX 0x14/disp8 . # copy *(ESP+20) to ECX + 81 0/subop/add 3/mod/direct 1/rm32/ECX . . . . . 4/imm32 # add 4 to ECX + # size = *s + 8b/copy 1/mod/*+disp8 4/rm32/SIB 4/base/ESP 4/index/none . 2/r32/EDX 0x14/disp8 . # copy *(ESP+20) to EDX + 8b/copy 0/mod/indirect 2/rm32/EDX . . . 2/r32/EDX . . # copy *EDX to EDX + # call write() + b8/copy . . . . . . . 4/imm32/write # copy 1 to EAX + cd/syscall 0x80/imm8 + # restore registers + 5b/pop . . . . . . . . # pop EBX + 5a/pop . . . . . . . . # pop EDX + 59/pop . . . . . . . . # pop ECX + 58/pop . . . . . . . . # pop EAX + # end + c3/return + +write_argv_3: # s : null-terminated ascii string of size exactly 3 -> <void> + # save registers + 50/push . . . . . . . . # push EAX + 51/push . . . . . . . . # push ECX + 52/push . . . . . . . . # push EDX + 53/push . . . . . . . . # push EBX + # write(2/stderr, (data) s+4, (size) *s) + # fd = 2 (stderr) + bb/copy . . . . . . . 2/imm32 # copy 2 to EBX + # x = s + 8b/copy 1/mod/*+disp8 4/rm32/SIB 4/base/ESP 4/index/none . 1/r32/ECX 0x14/disp8 . # copy *(ESP+20) to ECX + # size = 3 + ba/copy . . . . . . . 3/imm32 # copy 3 to EDX (hardcoded) + # call write() + b8/copy . . . . . . . 4/imm32/write # copy 1 to EAX + cd/syscall 0x80/imm8 + # restore registers + 5b/pop . . . . . . . . # pop EBX + 5a/pop . . . . . . . . # pop EDX + 59/pop . . . . . . . . # pop ECX + 58/pop . . . . . . . . # pop EAX + # end + c3/return + +== data +X: + 02 00 00 00 + 58/X 0a/newline +Y: + 02 00 00 00 + 59/Y 0a/newline |