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| author | Kartik Agaram <vc@akkartik.com> | 2018-10-14 22:25:57 -0700 |
|---|---|---|
| committer | Kartik Agaram <vc@akkartik.com> | 2018-10-14 22:25:57 -0700 |
| commit | 6528a08992b3518c86628260c2318a792abaa6bd (patch) | |
| tree | c3125f2f254059ee978b2759f82dd5b4cd191c32 /subx/050write.subx | |
| parent | a9a5718d086d9df52b84b96a6ab4ee751dc26a5e (diff) | |
| download | mu-6528a08992b3518c86628260c2318a792abaa6bd.tar.gz | |
4699
Diffstat (limited to 'subx/050write.subx')
| -rw-r--r-- | subx/050write.subx | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/subx/050write.subx b/subx/050write.subx new file mode 100644 index 00000000..b687aa3d --- /dev/null +++ b/subx/050write.subx @@ -0,0 +1,44 @@ +== code + +# instruction effective address operand 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 + +# main: (manual test if this is the last file loaded) + # syscall(exit, 0) -- can't test these functions just yet + bb/copy-to-EBX 0/imm32 + b8/copy-to-EAX 1/imm32 + cd/syscall 0x80/imm8 + +_write: # fd : int, s : (address array byte) -> <void> + # prolog + 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, fd, (data) s+4, (size) *s) + # fd : EBX + 8b/copy 1/mod/*+disp8 4/rm32/sib 5/base/EBP 4/index/none . 3/r32/EBX 8/disp8 . # copy *(EBP+8) to EBX + # data : ECX = s+4 + 8b/copy 1/mod/*+disp8 4/rm32/sib 5/base/EBP 4/index/none . 1/r32/ECX 0xc/disp8 . # copy *(EBP+12) to ECX + 81 0/subop/add 3/mod/direct 1/rm32/ECX . . . . . 4/imm32 # add to ECX + # size : EDX = *s + 8b/copy 1/mod/*+disp8 4/rm32/sib 5/base/EBP 4/index/none . 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 + # syscall + b8/copy-to-EAX 4/imm32/write + cd/syscall 0x80/imm8 + # 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 + +# vim:nowrap:textwidth=0 |