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| author | Kartik K. Agaram <vc@akkartik.com> | 2021-05-19 23:14:27 -0700 |
|---|---|---|
| committer | Kartik K. Agaram <vc@akkartik.com> | 2021-05-19 23:14:27 -0700 |
| commit | 4b57c101b71727aa718216b90f7a255bab2427c6 (patch) | |
| tree | 594f24a2cdcd9d9a2c012bdaa704093e92453c43 /108write.subx | |
| parent | e2ab1b30b1a669425cb86ffa7def9529e7fa4fb1 (diff) | |
| download | mu-4b57c101b71727aa718216b90f7a255bab2427c6.tar.gz | |
more robust print-cell
It is used to print to the trace, and we shouldn't crash the whole computer just because the trace ran out of space.
Diffstat (limited to '108write.subx')
| -rw-r--r-- | 108write.subx | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/108write.subx b/108write.subx index a6e6d98c..9dc9742b 100644 --- a/108write.subx +++ b/108write.subx @@ -135,6 +135,79 @@ _test-stream: # (stream byte) == code +try-write: # f: (addr stream byte), s: (addr array byte) -> overflow?/eax: boolean + # . prologue + 55/push-ebp + 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp + # if (s == 0) return + 81 7/subop/compare 1/mod/*+disp8 5/rm32/ebp . . . . 0xc/disp8 0/imm32 # compare *(ebp+12) + 74/jump-if-= $write:end/disp8 + # . save registers + 51/push-ecx + # if (f->size - f->write < s->size) return + # . eax = f->size - f->write - s->size + 8b/copy 1/mod/*+disp8 5/rm32/ebp . . 1/r32/ecx 8/disp8 . # copy *(ebp+8) to ecx + 8b/copy 1/mod/*+disp8 1/rm32/ecx . . . 0/r32/eax 8/disp8 . # copy *(ecx+8) to eax + 2b/subtract 0/mod/indirect 1/rm32/ecx . . . 0/r32/eax . . # subtract *ecx from eax + 8b/copy 1/mod/*+disp8 5/rm32/ebp . . 1/r32/ecx 0xc/disp8 . # copy *(ebp+12) to ecx + 2b/subtract 0/mod/indirect 1/rm32/ecx . . . 0/r32/eax . . # subtract *ecx from eax + # . if (eax < 0) return + 3d/compare-eax-and 0/imm32 + 7c/jump-if-< $try-write:end/disp8 + # write(f, s) + # . . push args + ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 0xc/disp8 . # push *(ebp+12) + ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 8/disp8 . # push *(ebp+8) + # . . call + e8/call write/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp + # . restore registers + 59/pop-to-ecx + # return 0 + b8/copy-to-eax 0/imm32 +$try-write:end: + # . epilogue + 89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp + 5d/pop-to-ebp + c3/return + +# probably a bad idea +space-remaining-in-stream: # f: (addr stream byte) -> n/eax: int + # . prologue + 55/push-ebp + 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp + # . save registers + 51/push-ecx + # return f->size - f->write + 8b/copy 1/mod/*+disp8 5/rm32/ebp . . 1/r32/ecx 8/disp8 . # copy *(ebp+8) to ecx + 8b/copy 1/mod/*+disp8 1/rm32/ecx . . . 0/r32/eax 8/disp8 . # copy *(ecx+8) to eax + 2b/subtract 0/mod/indirect 1/rm32/ecx . . . 0/r32/eax . . # subtract *ecx from eax + # . restore registers + 59/pop-to-ecx +$space-remaining-in-stream:end: + # . epilogue + 89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp + 5d/pop-to-ebp + c3/return + +stream-size: # f: (addr stream byte) -> n/eax: int + # . prologue + 55/push-ebp + 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp + # . save registers + 51/push-ecx + # return f->write + 8b/copy 1/mod/*+disp8 5/rm32/ebp . . 1/r32/ecx 8/disp8 . # copy *(ebp+8) to ecx + 8b/copy 0/mod/indirect 1/rm32/ecx . . . 0/r32/eax . . # copy *ecx to eax + # . restore registers + 59/pop-to-ecx +$space-remaining-in-stream:end: + # . epilogue + 89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp + 5d/pop-to-ebp + c3/return + # 3-argument variant of _append _append-3: # out: (addr byte), outend: (addr byte), s: (addr array byte) -> num_bytes_appended/eax # . prologue @@ -142,6 +215,15 @@ _append-3: # out: (addr byte), outend: (addr byte), s: (addr array byte) -> num 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp # . save registers 51/push-ecx + # if (outend - out < s->size) abort + # . eax = f->size - f->write - s->size + 8b/copy 1/mod/*+disp8 5/rm32/ebp . . 0/r32/eax 0xc/disp8 . # copy *(ebp+12) to eax + 2b/subtract 1/mod/*+disp8 5/rm32/ebp . . . 0/r32/eax 8/disp8 . # subtract *(ebp+8) from eax + 8b/copy 1/mod/*+disp8 5/rm32/ebp . . 1/r32/ecx 0x10/disp8 . # copy *(ebp+16) to ecx + 2b/subtract 0/mod/indirect 1/rm32/ecx . . . 0/r32/eax . . # subtract *ecx from eax + # . if (eax < 0) abort + 3d/compare-eax-and 0/imm32 + 7c/jump-if-< $_append-3:abort/disp8 # eax = _append-4(out, outend, &s->data[0], &s->data[s->size]) # . . push &s->data[s->size] 8b/copy 1/mod/*+disp8 5/rm32/ebp . . 0/r32/eax 0x10/disp8 . # copy *(ebp+16) to eax @@ -167,6 +249,10 @@ $_append-3:end: 5d/pop-to-ebp c3/return +$_append-3:abort: + (abort "_append-3 about to overflow") # 3=cyan + # never gets here + # 4-argument variant of _append _append-4: # out: (addr byte), outend: (addr byte), in: (addr byte), inend: (addr byte) -> num_bytes_appended/eax: int # . prologue |