diff options
Diffstat (limited to 'linux/apps/crenshaw2-1.subx')
| -rw-r--r-- | linux/apps/crenshaw2-1.subx | 556 |
1 files changed, 556 insertions, 0 deletions
diff --git a/linux/apps/crenshaw2-1.subx b/linux/apps/crenshaw2-1.subx new file mode 100644 index 00000000..73c0f16e --- /dev/null +++ b/linux/apps/crenshaw2-1.subx @@ -0,0 +1,556 @@ +# Port of https://github.com/akkartik/crenshaw/blob/master/tutor2.1.pas +# which corresponds to the section "single digits" in https://compilers.iecc.com/crenshaw/tutor2.txt +# except that we support hex digits. +# +# To run: +# $ bootstrap/bootstrap translate [01]*.subx apps/crenshaw2-1.subx -o crenshaw2-1 +# $ echo '3' |bootstrap/bootstrap run crenshaw2-1 +# Expected output: +# # syscall(exit, 3) +# bb/copy-to-ebx 3/imm32 +# b8/copy-to-eax 1/imm32/exit +# cd/syscall 0x80/imm8 +# +# To run the generated output: +# $ echo '3' |bootstrap/bootstrap run crenshaw2-1 > z1.subx +# $ bootstrap/bootstrap translate z1.subx -o z1 +# $ bootstrap/bootstrap run z1 +# $ echo $? +# 3 +# +# Stdin must contain just a single hex digit. Other input will print an error: +# $ echo 'xyz' |bootstrap/bootstrap run crenshaw2-1 +# Error: integer expected +# +# Names in this file sometimes follow Crenshaw's original rather than my usual +# naming conventions. + +== 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: # run tests if necessary, call 'compile' if not + # . prologue + 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp + + # initialize heap + # . Heap = new-segment(Heap-size) + # . . push args + 68/push Heap/imm32 + ff 6/subop/push 0/mod/indirect 5/rm32/.disp32 . . . Heap-size/disp32 # push *Heap-size + # . . call + e8/call new-segment/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp + + # - if argc > 1 and argv[1] == "test", then return run_tests() + # if (argc <= 1) goto run-main + 81 7/subop/compare 1/mod/*+disp8 5/rm32/ebp . . . . 0/disp8 1/imm32 # compare *ebp + 7e/jump-if-<= $run-main/disp8 + # if (!kernel-string-equal?(argv[1], "test")) goto run-main + # . eax = kernel-string-equal?(argv[1], "test") + # . . push args + 68/push "test"/imm32 + ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 8/disp8 . # push *(ebp+8) + # . . call + e8/call kernel-string-equal?/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp + # . if (eax == false) goto run-main + 3d/compare-eax-and 0/imm32/false + 74/jump-if-= $run-main/disp8 + # run-tests() + e8/call run-tests/disp32 + # syscall(exit, *Num-test-failures) + 8b/copy 0/mod/indirect 5/rm32/.disp32 . . 3/r32/ebx Num-test-failures/disp32 # copy *Num-test-failures to ebx + eb/jump $main:end/disp8 +$run-main: + # - otherwise read a program from stdin and emit its translation to stdout + # . compile(Stdin, 1/stdout, 2/stderr, ed) + # . . push args + 68/push 0/imm32/exit-descriptor + 68/push 2/imm32/stderr + 68/push 1/imm32/stdout + 68/push Stdin/imm32 + # . . call + e8/call compile/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0x10/imm32 # add to esp + # syscall(exit, 0) + bb/copy-to-ebx 0/imm32 +$main:end: + e8/call syscall_exit/disp32 + +# the main entry point +compile: # in: (addr buffered-file), out: fd or (addr stream byte), err: fd or (addr stream byte), ed: (addr exit-descriptor) + # . 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 + # prime the pump + # . Look = get-char(in) + # . . push args + ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 8/disp8 . # push *(ebp+8) + # . . call + e8/call get-char/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp + # var num/ecx: (stream byte 7) + # Numbers can be 32 bits or 8 hex bytes long. One of them will be in 'Look', so we need space for 7 bytes. + # Sizing the stream just right buys us overflow-handling for free inside 'get-num'. + # Add 12 bytes for 'read', 'write' and 'size' fields, for a total of 19 bytes, or 0x13 in hex. + # The stack pointer is no longer aligned, so dump_stack() can be misleading past this point. + 81 5/subop/subtract 3/mod/direct 4/rm32/esp . . . . . 0x13/imm32 # subtract from esp + 89/copy 3/mod/direct 1/rm32/ecx . . . 4/r32/esp . . # copy esp to ecx + # initialize the stream + # . num->size = 7 + c7 0/subop/copy 1/mod/*+disp8 1/rm32/ecx . . . . 8/disp8 7/imm32 # copy to *(ecx+8) + # . clear-stream(num) + # . . push args + 51/push-ecx + # . . call + e8/call clear-stream/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp + # read a digit from 'in' into 'num' + # . get-num(in, num, err, ed) + # . . push args + ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 0x14/disp8 . # push *(ebp+20) + ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 0x10/disp8 . # push *(ebp+16) + 51/push-ecx/num + ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 8/disp8 . # push *(ebp+8) + # . . call + e8/call get-num/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0x10/imm32 # add to esp + # render 'num' into the following template on 'out': + # bb/copy-to-ebx _num_ + # b8/copy-to-eax 1/imm32/exit + # cd/syscall 0x80/imm8 + # + # . write(out, "bb/copy-to-ebx ") + # . . push args + 68/push "bb/copy-to-ebx "/imm32 + ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 0xc/disp8 . # push *(ebp+12) + # . . call + e8/call write/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp + # . write-stream(out, num) + # . . push args + 51/push-ecx/num + ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 0xc/disp8 . # push *(ebp+12) + # . . call + e8/call write-stream/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp + # . write(out, Newline) + # . . push args + 68/push Newline/imm32 + ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 0xc/disp8 . # push *(ebp+12) + # . . call + e8/call write/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp + # . write(out, "b8/copy-to-eax 1/imm32/exit\n") + # . . push args + 68/push "b8/copy-to-eax 1/imm32/exit\n"/imm32 + ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 0xc/disp8 . # push *(ebp+12) + # . . call + e8/call write/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp + # . write(out, "cd/syscall 0x80/imm8\n") + # . . push args + 68/push "cd/syscall 0x80/imm8\n"/imm32 + ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 0xc/disp8 . # push *(ebp+12) + # . . call + e8/call write/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp +$compile: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 + +# Read a single digit into 'out'. Abort if there are none, or if there is no +# space in 'out'. +# Input comes from the global variable 'Look' (first byte) and the argument +# 'in' (rest). We leave the next byte from 'in' into 'Look' on exit. +get-num: # in: (addr buffered-file), out: (addr stream byte), err: fd or (addr stream byte), ed: (addr exit-descriptor) + # pseudocode: + # if (!digit?(Look)) expected(ed, err, "integer") + # if out->write >= out->size + # write(err, "Error: too many digits in number\n") + # stop(ed, 1) + # out->data[out->write] = LSB(Look) + # ++out->write + # Look = get-char(in) + # + # registers: + # in: esi + # out: edi + # out->write: ecx (cached copy; need to keep in sync) + # out->size: edx + # temporaries: eax, ebx + # We can't allocate Look to a register because it gets written implicitly in + # get-char in each iteration of the loop. (Thereby demonstrating that it's + # not the right interface for us. But we'll keep it just to follow Crenshaw.) + # + # . prologue + 55/push-ebp + 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp + # - if (digit?(Look)) expected(ed, err, "integer") + # . eax = digit?(Look) + # . . push args + ff 6/subop/push 0/mod/indirect 5/rm32/.disp32 . . . Look/disp32 . # push *Look + # . . call + e8/call digit?/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp + # . if (eax == false) + 3d/compare-eax-and 0/imm32/false + 75/jump-if-!= $get-num:main/disp8 + # . expected(ed, err, "integer") + # . . push args + 68/push "integer"/imm32 + ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 0x10/disp8 . # push *(ebp+16) + ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 0x14/disp8 . # push *(ebp+20) + # . . call + e8/call expected/disp32 # never returns + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp +$get-num:main: + # - otherwise read a digit + # . save registers + 50/push-eax + 51/push-ecx + 52/push-edx + 53/push-ebx + 56/push-esi + 57/push-edi + # read necessary variables to registers + # esi = in + 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 6/r32/esi 8/disp8 . # copy *(ebp+8) to esi + # edi = out + 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 7/r32/edi 0xc/disp8 . # copy *(ebp+12) to edi + # ecx = out->write + 8b/copy 0/mod/indirect 7/rm32/edi . . . 1/r32/ecx . . # copy *edi to ecx + # edx = out->size + 8b/copy 1/mod/*+disp8 7/rm32/edi . . . 2/r32/edx 8/disp8 . # copy *(edi+8) to edx +$get-num:loop: + # if (out->write >= out->size) error + 39/compare 3/mod/direct 2/rm32/edx . . . 1/r32/ecx . . # compare edx with ecx + 7d/jump-if-< $get-num:stage2/disp8 + # . error(ed, err, msg) # TODO: show full number + # . . push args + 68/push "get-num: too many digits in number"/imm32 + ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 0x10/disp8 . # push *(ebp+16) + ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 0x14/disp8 . # push *(ebp+20) + # . . call + e8/call error/disp32 # never returns + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp +$get-num:stage2: + # out->data[out->write] = LSB(Look) + 8d/copy-address 1/mod/*+disp8 4/rm32/sib 7/base/edi 1/index/ecx . 3/r32/ebx 0xc/disp8 . # copy edi+ecx+12 to ebx + 8b/copy 0/mod/indirect 5/rm32/.disp32 . . 0/r32/eax Look/disp32 . # copy *Look to eax + 88/copy-byte 0/mod/indirect 3/rm32/ebx . . . 0/r32/AL . . # copy byte at AL to *ebx + # ++out->write + 41/increment-ecx + # Look = get-char(in) + # . . push args + 56/push-esi + # . . call + e8/call get-char/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp +$get-num:loop-end: + # persist necessary variables from registers + 89/copy 0/mod/indirect 7/rm32/edi . . . 1/r32/ecx . . # copy ecx to *edi +$get-num:end: + # . restore registers + 5f/pop-to-edi + 5e/pop-to-esi + 5b/pop-to-ebx + 5a/pop-to-edx + 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-get-num-reads-single-digit: + # - check that get-num returns first character if it's a digit + # This test uses exit-descriptors. Use ebp for setting up local variables. + 55/push-ebp + 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp + # clear all streams + # . clear-stream(_test-stream) + # . . push args + 68/push _test-stream/imm32 + # . . call + e8/call clear-stream/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp + # . clear-stream($_test-buffered-file->buffer) + # . . push args + 68/push $_test-buffered-file->buffer/imm32 + # . . call + e8/call clear-stream/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp + # . clear-stream(_test-output-stream) + # . . push args + 68/push _test-output-stream/imm32 + # . . call + e8/call clear-stream/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp + # . clear-stream(_test-error-stream) + # . . push args + 68/push _test-error-stream/imm32 + # . . call + e8/call clear-stream/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp + # initialize 'in' + # . write(_test-stream, "3") + # . . push args + 68/push "3"/imm32 + 68/push _test-stream/imm32 + # . . call + e8/call write/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp + # initialize exit-descriptor 'ed' for the call to 'get-num' below + # . var ed/eax: exit-descriptor + 81 5/subop/subtract 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # subtract from esp + 89/copy 3/mod/direct 0/rm32/eax . . . 4/r32/esp . . # copy esp to eax + # . tailor-exit-descriptor(ed, 16) + # . . push args + 68/push 0x10/imm32/nbytes-of-args-for-get-num + 50/push-eax/ed + # . . call + e8/call tailor-exit-descriptor/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp + # prime the pump + # . get-char(_test-buffered-file) + # . . push args + 68/push _test-buffered-file/imm32 + # . . call + e8/call get-char/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp + # get-num(in, out, err, ed) + # . . push args + 50/push-eax/ed + 68/push _test-error-stream/imm32 + 68/push _test-output-stream/imm32 + 68/push _test-buffered-file/imm32 + # . . call + e8/call get-num/disp32 + # registers except esp may be clobbered at this point + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0x10/imm32 # add to esp + # check-ints-equal(*_test-output-stream->data, '3', msg) + # . . push args + 68/push "F - test-get-num-reads-single-digit"/imm32 + 68/push 0x33/imm32 + b8/copy-to-eax _test-output-stream/imm32 + ff 6/subop/push 1/mod/*+disp8 0/rm32/eax . . . . 0xc/disp8 . # push *(eax+12) + # . . call + e8/call check-ints-equal/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp + # . reclaim locals + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp + 5d/pop-to-ebp + c3/return + +test-get-num-aborts-on-non-digit-in-Look: + # - check that get-num returns first character if it's a digit + # This test uses exit-descriptors. Use ebp for setting up local variables. + 55/push-ebp + 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp + # clear all streams + # . clear-stream(_test-stream) + # . . push args + 68/push _test-stream/imm32 + # . . call + e8/call clear-stream/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp + # . clear-stream($_test-buffered-file->buffer) + # . . push args + 68/push $_test-buffered-file->buffer/imm32 + # . . call + e8/call clear-stream/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp + # . clear-stream(_test-output-stream) + # . . push args + 68/push _test-output-stream/imm32 + # . . call + e8/call clear-stream/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp + # . clear-stream(_test-error-stream) + # . . push args + 68/push _test-error-stream/imm32 + # . . call + e8/call clear-stream/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp + # initialize 'in' + # . write(_test-stream, "3") + # . . push args + 68/push "3"/imm32 + 68/push _test-stream/imm32 + # . . call + e8/call write/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp + # initialize exit-descriptor 'ed' for the call to 'get-num' below + # . var ed/eax: exit-descriptor + 81 5/subop/subtract 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # subtract from esp + 89/copy 3/mod/direct 0/rm32/eax . . . 4/r32/esp . . # copy esp to eax + # . tailor-exit-descriptor(ed, 16) + # . . push args + 68/push 0x10/imm32/nbytes-of-args-for-get-num + 50/push-eax/ed + # . . call + e8/call tailor-exit-descriptor/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp + # *don't* prime the pump + # get-num(in, out, err, ed) + # . . push args + 50/push-eax/ed + 68/push _test-error-stream/imm32 + 68/push _test-output-stream/imm32 + 68/push _test-buffered-file/imm32 + # . . call + e8/call get-num/disp32 + # registers except esp may be clobbered at this point + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0x10/imm32 # add to esp + # check that get-num tried to call exit(1) + # . check-ints-equal(ed->value, 2, msg) # i.e. stop was called with value 1 + # . . push args + 68/push "F - test-get-num-aborts-on-non-digit-in-Look"/imm32 + 68/push 2/imm32 + # . . push ed->value + ff 6/subop/push 1/mod/*+disp8 0/rm32/eax . . . . 4/disp8 . # push *(eax+4) + # . . call + e8/call check-ints-equal/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp + # . reclaim locals + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp + 5d/pop-to-ebp + c3/return + +## helpers + +# write(f, "Error: "+s+" expected\n") then stop(ed, 1) +expected: # ed: (addr exit-descriptor), f: fd or (addr stream byte), s: (addr array byte) + # . prologue + 55/push-ebp + 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp + # write(f, "Error: ") + # . . push args + 68/push "Error: "/imm32 + ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 0xc/disp8 . # push *(ebp+12) + # . . call + e8/call write/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp + # write(f, s) + # . . push args + ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 0x10/disp8 . # push *(ebp+16) + ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 0xc/disp8 . # push *(ebp+12) + # . . call + e8/call write/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp + # write(f, " expected\n") + # . . push args + 68/push " expected\n"/imm32 + ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 0xc/disp8 . # push *(ebp+12) + # . . call + e8/call write/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp + # stop(ed, 1) + # . . push args + 68/push 1/imm32 + ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 8/disp8 . # push *(ebp+8) + # . . call + e8/call stop/disp32 + # should never get past this point +$expected:dead-end: + # . epilogue + 89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp + 5d/pop-to-ebp + c3/return + +# read a byte from 'f', and save it in 'Look' +get-char: # f: (addr buffered-file) + # . prologue + 55/push-ebp + 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp + # . save registers + 50/push-eax + # eax = read-byte-buffered(f) + # . . push args + ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 8/disp8 . # push *(ebp+8) + # . . call + e8/call read-byte-buffered/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp + # save eax to Look + 89/copy 0/mod/indirect 5/rm32/.disp32 . . 0/r32/eax Look/disp32 . # copy eax to *Look +$get-char:end: + # . restore registers + 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 + +digit?: # c: int -> eax: boolean + # . prologue + 55/push-ebp + 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp + # eax = false + b8/copy-to-eax 0/imm32 + # if (c < '0') return false + 81 7/subop/compare 1/mod/*+disp8 5/rm32/ebp . . . . 8/disp8 0x30/imm32 # compare *(ebp+8) + 7c/jump-if-< $digit?:end/disp8 + # if (c > '9') return false + 81 7/subop/compare 1/mod/*+disp8 5/rm32/ebp . . . . 8/disp8 0x39/imm32 # compare *(ebp+8) + 7f/jump-if-> $digit?:end/disp8 + # otherwise return true + b8/copy-to-eax 1/imm32 +$digit?:end: + # . epilogue + 89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp + 5d/pop-to-ebp + c3/return + +== data + +Look: # (char with some extra padding) + 0/imm32 + +# . . vim:nowrap:textwidth=0 |