diff options
Diffstat (limited to 'linux/203stack.subx')
| -rw-r--r-- | linux/203stack.subx | 416 |
1 files changed, 416 insertions, 0 deletions
diff --git a/linux/203stack.subx b/linux/203stack.subx new file mode 100644 index 00000000..965f7301 --- /dev/null +++ b/linux/203stack.subx @@ -0,0 +1,416 @@ +# A stack looks like this: +# top: int +# data: (array byte) # prefixed by size as usual +# +# TODO: is it confusing that the push opcodes grow memory downward, but the +# push function grows stacks upward? + +== 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 + +clear-stack: # s: (addr stack) + # . prologue + 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 + # eax = s + 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 0/r32/eax 8/disp8 . # copy *(ebp+8) to eax + # var max/ecx: (addr byte) = &s->data[s->size] + 8b/copy 1/mod/*+disp8 0/rm32/eax . . . 1/r32/ecx 4/disp8 . # copy *(eax+4) to eax + 8d/copy-address 1/mod/*+disp8 4/rm32/sib 0/base/eax 1/index/ecx . 1/r32/ecx 8/disp8 . # copy eax+ecx+8 to ecx + # s->top = 0 + c7 0/subop/copy 0/mod/direct 0/rm32/eax . . . . . 0/imm32 # copy to *eax + # var curr/eax: (addr byte) = s->data + 81 0/subop/add 3/mod/direct 0/rm32/eax . . . . . 8/imm32 # add to eax +$clear-stack:loop: + # if (curr >= max) break + 39/compare 3/mod/direct 0/rm32/eax . . . 1/r32/ecx . . # compare eax with ecx + 73/jump-if-addr>= $clear-stack:end/disp8 + # *curr = 0 + c6 0/subop/copy-byte 0/mod/direct 0/rm32/eax . . . . . 0/imm8 # copy byte to *eax + # ++curr + 40/increment-eax + eb/jump $clear-stack:loop/disp8 +$clear-stack:end: + # . restore registers + 59/pop-to-ecx + 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-clear-stack: + # . prologue + 55/push-ebp + 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp + # var stack/ecx = stack of size 8 with random data in it + 68/push 34/imm32 + 68/push 35/imm32 + 68/push 8/imm32/size + 68/push 14/imm32/top + 89/copy 3/mod/direct 1/rm32/ecx . . . 4/r32/esp . . # copy esp to ecx + # clear(stack) + # . . push args + 51/push-ecx + # . . call + e8/call clear-stack/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp + # top should be 0 + 58/pop-to-eax + # . check-ints-equal(eax, 0, msg) + # . . push args + 68/push "F - test-clear-stack: top"/imm32 + 68/push 0/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 + # size should remain 8 + 58/pop-to-eax + # . check-ints-equal(eax, 8, msg) + # . . push args + 68/push "F - test-clear-stack: size"/imm32 + 68/push 8/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 + # first word is 0 + 58/pop-to-eax + # . check-ints-equal(eax, 0, msg) + # . . push args + 68/push "F - test-clear-stack: data[0..3]"/imm32 + 68/push 0/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 + # second word is 0 + 58/pop-to-eax + # . check-ints-equal(eax, 0, msg) + # . . push args + 68/push "F - test-clear-stack: data[4..7]"/imm32 + 68/push 0/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 + # . epilogue + 89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp + 5d/pop-to-ebp + c3/return + +# TODO: make this generic +push: # s: (addr stack), n: int + # . prologue + 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 + 56/push-esi + # esi = s + 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 6/r32/esi 8/disp8 . # copy *(ebp+8) to esi + # ecx = s->top + 8b/copy 0/mod/indirect 6/rm32/esi . . . 1/r32/ecx . . # copy *esi to ecx + # if (s->top >= s->size) abort + 39/compare 1/mod/*+disp8 6/rm32/esi . . . 1/r32/ecx 4/disp8 . # compare *(esi+4) and ecx + 7e/jump-if-<= $push:abort/disp8 + # s->data[s->top] = n + 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 0/r32/eax 0xc/disp8 . # copy *(ebp+12) to eax + 89/copy 1/mod/*+disp8 4/rm32/sib 6/base/esi 1/index/ecx . 0/r32/eax 8/disp8 . # copy eax to *(esi+ecx+8) + # s->top += 4 + 81 0/subop/add 0/mod/direct 6/rm32/esi . . . . . 4/imm32 # subtract from *esi +$push:end: + # . restore registers + 5e/pop-to-esi + 59/pop-to-ecx + 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 + +$push:abort: + # print(stderr, "error: push: no space left") + # . write-buffered(Stderr, "error: push: no space left") + # . . push args + 68/push "error: push: no space left"/imm32 + 68/push Stderr/imm32 + # . . call + e8/call write-buffered/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp + # . flush(Stderr) + # . . push args + 68/push Stderr/imm32 + # . . call + e8/call flush/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp + # . syscall(exit, 1) + bb/copy-to-ebx 1/imm32 + e8/call syscall_exit/disp32 + # never gets here + +test-push: + # . prologue + 55/push-ebp + 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp + # var stack/ecx = empty stack of size 8 + 68/push 0/imm32 + 68/push 0/imm32 + 68/push 8/imm32/size + 68/push 0/imm32/top + 89/copy 3/mod/direct 1/rm32/ecx . . . 4/r32/esp . . # copy esp to ecx + # push(stack, 0x42) + # . . push args + 68/push 0x42/imm32 + 51/push-ecx + # . . call + e8/call push/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp + # check top + 58/pop-to-eax + # . check-ints-equal(eax, 4, msg) + # . . push args + 68/push "F - test-push: top"/imm32 + 68/push 4/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 size + 58/pop-to-eax + # . check-ints-equal(eax, 8, msg) + # . . push args + 68/push "F - test-push: size"/imm32 + 68/push 8/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 + # first word is 0x42 + 58/pop-to-eax + # . check-ints-equal(eax, 0x42, msg) + # . . push args + 68/push "F - test-push: data[0..3]"/imm32 + 68/push 0x42/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 + # second word is 0 + 58/pop-to-eax + # . check-ints-equal(eax, 0, msg) + # . . push args + 68/push "F - test-push: data[4..7]"/imm32 + 68/push 0/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 + # . epilogue + 89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp + 5d/pop-to-ebp + c3/return + +# TODO: make this generic +pop: # s: (addr stack) -> 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 + 56/push-esi + # esi = s + 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 6/r32/esi 8/disp8 . # copy *(ebp+8) to esi + # if (s->top <= 0) abort + 81 7/subop/compare 0/mod/indirect 6/rm32/esi . . . . . 0/imm32 # compare *esi + 7e/jump-if-<= $pop:abort/disp8 + # s->top -= 4 + 81 5/subop/subtract 0/mod/direct 6/rm32/esi . . . . . 4/imm32 # subtract from *esi + # eax = s->data[s->top] + 8b/copy 0/mod/indirect 6/rm32/esi . . . 1/r32/ecx . . # copy *esi to ecx + 8b/copy 1/mod/*+disp8 4/rm32/sib 6/base/esi 1/index/ecx . 0/r32/eax 8/disp8 . # copy *(esi+ecx+8) to eax + # s->data[s->top] = 0 + c7 0/subop/copy 1/mod/*+disp8 4/rm32/sib 6/base/esi 1/index/ecx . 0/r32/eax 8/disp8 0/imm32 # copy to *(esi+ecx+8) +$pop:end: + # . restore registers + 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 + +$pop:abort: + # print(stderr, "error: pop: nothing left in stack") + # . write-buffered(Stderr, "error: pop: nothing left in stack") + # . . push args + 68/push "error: pop: nothing left in stack"/imm32 + 68/push Stderr/imm32 + # . . call + e8/call write-buffered/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp + # . flush(Stderr) + # . . push args + 68/push Stderr/imm32 + # . . call + e8/call flush/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp + # . syscall(exit, 1) + bb/copy-to-ebx 1/imm32 + e8/call syscall_exit/disp32 + # never gets here + +test-pop: + # . prologue + 55/push-ebp + 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp + # var stack/ecx = stack of size 8 containing just 0x42 + 68/push 0/imm32 + 68/push 0x42/imm32 + 68/push 8/imm32/size + 68/push 4/imm32/top + 89/copy 3/mod/direct 1/rm32/ecx . . . 4/r32/esp . . # copy esp to ecx + # eax = pop(stack) + # . . push args + 51/push-ecx + # . . call + e8/call pop/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp + # check-ints-equal(eax, 0x42, msg) + # . . push args + 68/push "F - test-pop: result"/imm32 + 68/push 0x42/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 top + 58/pop-to-eax + # . check-ints-equal(eax, 0, msg) + # . . push args + 68/push "F - test-pop: top"/imm32 + 68/push 0/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 size + 58/pop-to-eax + # . check-ints-equal(eax, 8, msg) + # . . push args + 68/push "F - test-pop: size"/imm32 + 68/push 8/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 + # . epilogue + 89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp + 5d/pop-to-ebp + c3/return + +# TODO: make this generic +top: # s: (addr stack) -> 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 + 56/push-esi + # esi = s + 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 6/r32/esi 8/disp8 . # copy *(ebp+8) to esi + # if (s->top <= 0) abort + 81 7/subop/compare 0/mod/indirect 6/rm32/esi . . . . . 0/imm32 # compare *esi + 7e/jump-if-<= $top:abort/disp8 + # n = s->data[s->top - 4] + 8b/copy 0/mod/indirect 6/rm32/esi . . . 1/r32/ecx . . # copy *esi to ecx + 81 5/subop/subtract 3/mod/direct 1/rm32/ecx . . . . . 4/imm32 # subtract from ecx + 8b/copy 1/mod/*+disp8 4/rm32/sib 6/base/esi 1/index/ecx . 0/r32/eax 8/disp8 . # copy *(esi+ecx+8) to eax +$top:end: + # . restore registers + 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 + +$top:abort: + # print(stderr, "error: top: nothing left in stack") + # . write-buffered(Stderr, "error: top: nothing left in stack") + # . . push args + 68/push "error: top: nothing left in stack"/imm32 + 68/push Stderr/imm32 + # . . call + e8/call write-buffered/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp + # . flush(Stderr) + # . . push args + 68/push Stderr/imm32 + # . . call + e8/call flush/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp + # . syscall(exit, 1) + bb/copy-to-ebx 1/imm32 + e8/call syscall_exit/disp32 + # never gets here + +test-top: + # . prologue + 55/push-ebp + 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp + # var stack/ecx = stack of size 8 containing just 0x42 + 68/push 0/imm32 + 68/push 0x42/imm32 + 68/push 8/imm32/size + 68/push 4/imm32/top + 89/copy 3/mod/direct 1/rm32/ecx . . . 4/r32/esp . . # copy esp to ecx + # eax = top(stack) + # . . push args + 51/push-ecx + # . . call + e8/call top/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp + # check-ints-equal(eax, 42, msg") + # . . push args + 68/push "F - test-top: result"/imm32 + 68/push 0x42/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 + # . epilogue + 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 |