diff options
Diffstat (limited to 'subx/071read-line.subx')
| -rw-r--r-- | subx/071read-line.subx | 94 |
1 files changed, 22 insertions, 72 deletions
diff --git a/subx/071read-line.subx b/subx/071read-line.subx index eff6f9c4..b16170b6 100644 --- a/subx/071read-line.subx +++ b/subx/071read-line.subx @@ -3,10 +3,17 @@ # . 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 a single test, while debugging +#? e8/call test-read-line/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 +#? b8/copy-to-EAX 1/imm32/exit +#? cd/syscall 0x80/imm8 + # read bytes from 'f' until (and including) a newline and store them into 's' -# return true if no data found, false otherwise +# 's' fails to grow if and only if no data found # just abort if 's' is too small -read-line: # f : (address buffered-file), s : (address stream byte) -> eof?/EAX +read-line: # f : (address buffered-file), s : (address stream byte) -> <void> # pseudocode: # loop: # if (s->write >= s->length) abort @@ -21,6 +28,7 @@ read-line: # f : (address buffered-file), s : (address stream byte) -> eof?/EAX 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 @@ -58,13 +66,11 @@ $read-line:loop: e8/call read/disp32 # . . discard args 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP - # if (f->write == 0) return true + # if (f->write == 0) break # since f->read was initially 0, EAX is the same as f->write # . if (EAX == 0) return true 81 7/subop/compare 3/mod/direct 0/rm32/EAX . . . . . 0/imm32 # compare EAX - 75/jump-if-not-equal $read-line:from-stream/disp8 - b8/copy-to-EAX 0xffffffff/imm32/Eof - eb/jump $read-line:end/disp8 + 74/jump-if-equal $read-line:end/disp8 $read-line:from-stream: # AL = f->data[f->read] 31/xor 3/mod/direct 0/rm32/EAX . . . 0/r32/EAX . . # clear EAX @@ -75,10 +81,9 @@ $read-line:from-stream: 41/increment-ECX # ++s->write 42/increment-EDX - # if (AL == '\n') return false + # if (AL == '\n') return 81 7/subop/compare 3/mod/direct 0/rm32/EAX . . . . . 0xa/imm32 # compare EAX 75/jump-if-not-equal $read-line:loop/disp8 - 31/xor 3/mod/direct 0/rm32/EAX . . . 0/r32/EAX . . # clear EAX $read-line:end: # save f->read 89/copy 1/mod/*+disp8 6/rm32/ESI . . . 1/r32/ECX 8/disp8 . # copy ECX to *(ESI+8) @@ -89,6 +94,7 @@ $read-line:end: 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 @@ -103,6 +109,14 @@ $read-line:abort: e8/call _write/disp32 # . . discard args 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP + # . _write(2/stderr, Newline) + # . . push args + 68/push Newline/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 @@ -169,15 +183,6 @@ test-read-line: e8/call read-line/disp32 # . . discard args 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP - # check-ints-equal(EAX, 0/not-at-Eof, msg) - # . . push args - 68/push "F - test-read-line: return value"/imm32 - 68/push 0/imm32/not-at-Eof - 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-next-stream-line-equal(_test-tmp-stream, "ab", msg) # . . push args 68/push "F - test-read-line"/imm32 @@ -190,52 +195,6 @@ test-read-line: # end c3/return -test-read-line-returns-true-on-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-buffered-file+4) - # . . push args - b8/copy-to-EAX _test-buffered-file/imm32 - 05/add-to-EAX 4/imm32 - 50/push-EAX - # . . 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 nothing - # EAX = read-line(_test-buffered-file, _test-tmp-stream) - # . . push args - 68/push _test-tmp-stream/imm32 - 68/push _test-buffered-file/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-ints-equal(EAX, Eof, msg) - # . . push args - 68/push "F - test-read-line-returns-true-on-Eof"/imm32 - 68/push 0xffffffff/imm32/Eof - 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 - # end - c3/return - test-read-line-reads-final-line-until-Eof: # setup # . clear-stream(_test-stream) @@ -278,15 +237,6 @@ test-read-line-reads-final-line-until-Eof: e8/call read-line/disp32 # . . discard args 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP - # check-ints-equal(EAX, Eof, msg) - # . . push args - 68/push "F - test-read-line-reads-final-line-until-Eof: return value"/imm32 - 68/push 0xffffffff/imm32/Eof - 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-stream-equal(_test-tmp-stream, "cd", msg) # . . push args 68/push "F - test-read-line-reads-final-line-until-Eof"/imm32 |