diff options
Diffstat (limited to 'subx/071read-line.subx')
| -rw-r--r-- | subx/071read-line.subx | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/subx/071read-line.subx b/subx/071read-line.subx index 9189773c..0add5568 100644 --- a/subx/071read-line.subx +++ b/subx/071read-line.subx @@ -217,4 +217,175 @@ test-read-line-buffered-reads-final-line-until-Eof: # end c3/return +# read bytes from 'f' until (and including) a newline and store them into 's' +# 's' fails to grow if and only if no data found +# just abort if 's' is too small +read-line: # f : (address stream), s : (address stream byte) -> <void> + # pseudocode: + # while true + # if (s->write >= s->length) abort + # if (f->read >= f->write) break + # AL = f->data[f->read] + # s->data[s->write] = AL + # ++f->read + # ++s->write + # if (AL == '\n') break + # . 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 + 56/push-ESI + 57/push-EDI + # ESI = f + 8b/copy 1/mod/*+disp8 5/rm32/EBP . . . 6/r32/ESI 8/disp8 . # copy *(EBP+8) to ESI + # ECX = f->read + 8b/copy 1/mod/*+disp8 6/rm32/ESI . . . 1/r32/ECX 4/disp8 . # copy *(ESI+4) to ECX + # EDI = s + 8b/copy 1/mod/*+disp8 5/rm32/EBP . . . 7/r32/EDI 0xc/disp8 . # copy *(EBP+12) to EDI + # EDX = s->write + 8b/copy 0/mod/indirect 7/rm32/EDI . . . 2/r32/EDX . . # copy *EDI to EDX +$read-line:loop: + # if (s->write >= s->length) abort + 3b/compare 1/mod/*+disp8 7/rm32/EDI . . . 2/r32/EDX 8/disp8 . # compare EDX with *(EDI+8) + 0f 8d/jump-if-greater-or-equal $read-line:abort/disp32 + # if (f->read >= f->write) break + 3b/compare 0/mod/indirect 6/rm32/ESI . . . 1/r32/ECX . . # compare ECX with *ESI + 7d/jump-if-greater-or-equal $read-line:end/disp8 + # AL = f->data[f->read] + 31/xor 3/mod/direct 0/rm32/EAX . . . 0/r32/EAX . . # clear EAX + 8a/copy-byte 1/mod/*+disp8 4/rm32/sib 6/base/ESI 1/index/ECX . 0/r32/AL 0xc/disp8 . # copy byte at *(ESI+ECX+12) to AL + # s->data[s->write] = AL + 88/copy-byte 1/mod/*+disp8 4/rm32/sib 7/base/EDI 2/index/EDX . 0/r32/AL 0xc/disp8 . # copy AL to *(EDI+EDX+12) + # ++f->read + 41/increment-ECX + # ++s->write + 42/increment-EDX + # if (AL == '\n') return + 3d/compare-EAX-and 0xa/imm32 + 0f 85/jump-if-not-equal $read-line:loop/disp32 +$read-line:end: + # save f->read + 89/copy 1/mod/*+disp8 6/rm32/ESI . . . 1/r32/ECX 4/disp8 . # copy ECX to *(ESI+4) + # save s->write + 89/copy 0/mod/indirect 7/rm32/EDI . . . 2/r32/EDX . . # copy EDX to *EDI + # . restore registers + 5f/pop-to-EDI + 5e/pop-to-ESI + 5a/pop-to-EDX + 59/pop-to-ECX + 58/pop-to-EAX + # . epilog + 89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP + 5d/pop-to-EBP + c3/return + +$read-line:abort: + # . _write(2/stderr, error) + # . . push args + 68/push "read-line: line too long\n"/imm32 + 68/push 2/imm32/stderr + # . . call + e8/call _write/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP + # . syscall(exit, 1) + bb/copy-to-EBX 1/imm32 + b8/copy-to-EAX 1/imm32/exit + cd/syscall 0x80/imm8 + # never gets here + +test-read-line: + # - check that read-line stops at a newline + # setup + # . 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-tmp-stream) + # . . push args + 68/push _test-tmp-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 + # write(_test-stream, "ab\ncd") + # . . push args + 68/push "ab\ncd"/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 + # read a line from _test-stream into _test-tmp-stream + # . EAX = read-line(_test-stream, _test-tmp-stream) + # . . push args + 68/push _test-tmp-stream/imm32 + 68/push _test-stream/imm32 + # . . call + e8/call read-line/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP + # check-next-stream-line-equal(_test-tmp-stream, "ab", msg) + # . . push args + 68/push "F - test-read-line"/imm32 + 68/push "ab"/imm32 + 68/push _test-tmp-stream/imm32 + # . . call + e8/call check-next-stream-line-equal/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP + # end + c3/return + +test-read-line-reads-final-line-until-Eof: + # setup + # . 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-tmp-stream) + # . . push args + 68/push _test-tmp-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 + # write(_test-stream, "cd") + # . . push args + 68/push "cd"/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 + # read a line from _test-stream into _test-tmp-stream + # . EAX = read-line(_test-stream, _test-tmp-stream) + # . . push args + 68/push _test-tmp-stream/imm32 + 68/push _test-stream/imm32 + # . . call + e8/call read-line/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP + # check-stream-equal(_test-tmp-stream, "cd", msg) + # . . push args + 68/push "F - test-read-line-reads-final-line-until-Eof"/imm32 + 68/push "cd"/imm32 + 68/push _test-tmp-stream/imm32 + # . . call + e8/call check-stream-equal/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP + # end + c3/return + # . . vim:nowrap:textwidth=0 |