diff options
Diffstat (limited to 'apps/ex10.subx')
| -rw-r--r-- | apps/ex10.subx | 69 |
1 files changed, 0 insertions, 69 deletions
diff --git a/apps/ex10.subx b/apps/ex10.subx deleted file mode 100644 index 7ec86202..00000000 --- a/apps/ex10.subx +++ /dev/null @@ -1,69 +0,0 @@ -# String comparison: return 1 iff the two args passed in at the commandline are equal. -# -# To run: -# $ ./bootstrap translate init.linux apps/ex10.subx -o apps/ex10 -# $ ./bootstrap run apps/ex10 abc abd -# Expected result: -# $ echo $? -# 0 # false - -== code -# instruction effective address register displacement immediate -# . op subop mod rm32 base index scale r32 -# . 1-3 bytes 3 bits 2 bits 3 bits 3 bits 3 bits 2 bits 2 bits 0/1/2/4 bytes 0/1/2/4 bytes - -Entry: # return argv-equal(argv[1], argv[2]) -# At the start of a SubX program: -# argc: *esp -# argv[0]: *(esp+4) -# argv[1]: *(esp+8) -# ... - # . prologue - 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp - # argv-equal(argv[1], argv[2]) - # . . push argv[2] - ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 0xc/disp8 . # push *(ebp+12) - # . . push argv[1] - ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 8/disp8 . # push *(ebp+8) - # . . call - e8/call argv-equal/disp32 - # exit(eax) - 89/copy 3/mod/direct 3/rm32/ebx . . . 0/r32/eax . . # copy eax to ebx - e8/call syscall_exit/disp32 - -# compare two null-terminated ascii strings -# reason for the name: the only place we should have null-terminated ascii strings is from commandline args -argv-equal: # (s1, s2): null-terminated ascii strings -> eax: boolean - # initialize s1 (ecx) and s2 (edx) - 8b/copy 1/mod/*+disp8 4/rm32/sib 4/base/esp 4/index/none . 1/r32/ecx 4/disp8 . # copy *(esp+4) to ecx - 8b/copy 1/mod/*+disp8 4/rm32/sib 4/base/esp 4/index/none . 2/r32/edx 8/disp8 . # copy *(esp+8) to edx -$argv-equal:loop: - # c1/eax, c2/ebx = *s1, *s2 - b8/copy-to-eax 0/imm32 - 8a/copy-byte 0/mod/indirect 1/rm32/ecx . . . 0/r32/AL . . # copy byte at *ecx to AL - bb/copy-to-ebx 0/imm32 - 8a/copy-byte 0/mod/indirect 2/rm32/edx . . . 3/r32/BL . . # copy byte at *edx to BL - # if (c1 == 0) break - 3d/compare-eax-and 0/imm32/null - 74/jump-if-= $argv-equal:break/disp8 - # if (c1 != c2) return false - 39/compare 3/mod/direct 0/rm32/eax . . . 3/r32/ebx . . # compare eax and ebx - 75/jump-if-!= $argv-equal:false/disp8 - # ++s1, ++s2 - 41/increment-ecx - 42/increment-edx - # end while - eb/jump $argv-equal:loop/disp8 -$argv-equal:break: - # if (c2 == 0) return true - 81 7/subop/compare 3/mod/direct 3/rm32/ebx . . . . . 0/imm32/null # compare ebx - 75/jump-if-!= $argv-equal:false/disp8 -$argv-equal:success: - b8/copy-to-eax 1/imm32 - c3/return - # return false -$argv-equal:false: - b8/copy-to-eax 0/imm32 - c3/return - -# . . vim:nowrap:textwidth=0 |