diff options
Diffstat (limited to 'subx/064write-byte.subx')
| -rw-r--r-- | subx/064write-byte.subx | 288 |
1 files changed, 0 insertions, 288 deletions
diff --git a/subx/064write-byte.subx b/subx/064write-byte.subx deleted file mode 100644 index 057b9164..00000000 --- a/subx/064write-byte.subx +++ /dev/null @@ -1,288 +0,0 @@ -# write-byte-buffered: add a single byte to a buffered-file. -# flush: write out any buffered writes to disk. -# -# TODO: Come up with a way to signal failure to write to disk. This is hard -# since the failure may impact previous calls that were buffered. - -== data - -# The buffered file for standard output. -Stdout: - # file descriptor or (address stream) - 1/imm32 # standard output - # current write index - 0/imm32 - # current read index - 0/imm32 - # length - 8/imm32 - # data - 00 00 00 00 00 00 00 00 # 8 bytes - -# TODO: 8 bytes is too small. We'll need to grow the buffer for efficiency. But -# I don't want to type in 1024 bytes here. - -== 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 - -# Write lower byte of 'n' to 'f'. -write-byte-buffered: # f : (address buffered-file), n : int -> <void> - # . prolog - 55/push-EBP - 89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP - # . save registers - 51/push-ECX - 57/push-EDI - # EDI = f - 8b/copy 1/mod/*+disp8 5/rm32/EBP . . . 7/r32/EDI 8/disp8 . # copy *(EBP+8) to EDI - # ECX = f->write - 8b/copy 1/mod/*+disp8 7/rm32/EDI . . . 1/r32/ECX 4/disp8 . # copy *(EDI+4) to ECX - # if (f->write >= f->length) flush and clear f's stream - 3b/compare 1/mod/*+disp8 7/rm32/EDI . . . 1/r32/ECX 0xc/disp8 . # compare ECX with *(EDI+12) - 7c/jump-if-lesser $write-byte-buffered:to-stream/disp8 - # . flush(f) - # . . push args - 57/push-EDI - # . . call - e8/call flush/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP - # . clear-stream(stream = f+4) - # . . push args - 8d/copy-address 1/mod/*+disp8 7/rm32/EDI . . . 0/r32/EAX 4/disp8 . # copy EDI+4 to EAX - 50/push-EAX - # . . call - e8/call clear-stream/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP - # . f->write must now be 0; update its cache at ECX - 31/xor 3/mod/direct 1/rm32/ECX . . . 1/r32/ECX . . # clear ECX -$write-byte-buffered:to-stream: - # write to stream - # f->data[f->write] = LSB(n) - 31/xor 3/mod/direct 0/rm32/EAX . . . 0/r32/EAX . . # clear EAX - 8a/copy-byte 1/mod/*+disp8 5/rm32/EBP . . . 0/r32/AL 0xc/disp8 . # copy byte at *(EBP+12) to AL - 88/copy-byte 1/mod/*+disp8 4/rm32/sib 7/base/EDI 1/index/ECX . 0/r32/AL 0x10/disp8 . # copy AL to *(EDI+ECX+16) - # ++f->write - ff 0/subop/increment 1/mod/*+disp8 7/rm32/EDI . . . . 4/disp8 . # increment *(EDI+4) -$write-byte-buffered:end: - # . restore registers - 5f/pop-to-EDI - 59/pop-to-ECX - # . epilog - 89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP - 5d/pop-to-EBP - c3/return - -flush: # f : (address buffered-file) -> <void> - # . prolog - 55/push-EBP - 89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP - # . save registers - 50/push-EAX - 51/push-ECX - # EAX = f - 8b/copy 1/mod/*+disp8 5/rm32/EBP . . . 0/r32/EAX 8/disp8 . # copy *(EBP+8) to EAX - # write-stream(f->fd, data = f+4) - # . . push args - 8d/copy-address 1/mod/*+disp8 0/rm32/EAX . . . 1/r32/ECX 4/disp8 . # copy EAX+4 to ECX - 51/push-ECX - ff 6/subop/push 0/mod/indirect 0/rm32/EAX . . . . . . # push *EAX - # . . call - e8/call write-stream/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP -$flush:end: - # . restore registers - 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 - -test-write-byte-buffered-single: - # - check that write-byte-buffered writes to first byte of 'file' - # 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 - # write-byte-buffered(_test-buffered-file, 'A') - # . . push args - 68/push 0x41/imm32 - 68/push _test-buffered-file/imm32 - # . . call - e8/call write-byte-buffered/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP - # flush(_test-buffered-file) - # . . push args - 68/push _test-buffered-file/imm32 - # . . call - e8/call flush/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP - # check-stream-equal(_test-stream, "A", msg) - # . . push args - 68/push "F - test-write-byte-buffered-single"/imm32 - 68/push "A"/imm32 - 68/push _test-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 - -test-write-byte-buffered-multiple-flushes: - # - check that write-byte-buffered correctly flushes buffered data - # 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 - # fill up the buffer for _test-buffered-file - # . write(_test-buffered-file+4, 'abcdef') - # . . push args - 68/push "abcdef"/imm32 - b8/copy-to-EAX _test-buffered-file/imm32 - 05/add-to-EAX 4/imm32 - 50/push-EAX - # . . call - e8/call write/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP - # write-byte-buffered(_test-buffered-file, 'g') - # . . push args - 68/push 0x67/imm32 - 68/push _test-buffered-file/imm32 - # . . call - e8/call write-byte-buffered/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP - # flush(_test-buffered-file) - # . . push args - 68/push _test-buffered-file/imm32 - # . . call - e8/call flush/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP - # check-stream-equal(_test-stream, "abcdef", msg) - # . . push args - 68/push "F - test-write-byte-buffered-multiple-flushes: 1"/imm32 - 68/push "abcdefg"/imm32 - 68/push _test-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 - -# - variant without buffering - -# Write lower byte of 'n' to 'f'. -append-byte: # f : (address stream), n : int -> <void> - # . prolog - 55/push-EBP - 89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP - # . save registers - 51/push-ECX - 57/push-EDI - # EDI = f - 8b/copy 1/mod/*+disp8 5/rm32/EBP . . . 7/r32/EDI 8/disp8 . # copy *(EBP+8) to EDI - # ECX = f->write - 8b/copy 0/mod/indirect 7/rm32/EDI . . . 1/r32/ECX . . # copy *EDI to ECX - # if (f->write >= f->length) abort - 3b/compare 1/mod/*+disp8 7/rm32/EDI . . . 1/r32/ECX 8/disp8 . # compare ECX with *(EDI+8) - 7d/jump-if-greater-or-equal $append-byte:abort/disp8 -$append-byte:to-stream: - # write to stream - # f->data[f->write] = LSB(n) - 31/xor 3/mod/direct 0/rm32/EAX . . . 0/r32/EAX . . # clear EAX - 8a/copy-byte 1/mod/*+disp8 5/rm32/EBP . . . 0/r32/AL 0xc/disp8 . # copy byte at *(EBP+12) to AL - 88/copy-byte 1/mod/*+disp8 4/rm32/sib 7/base/EDI 1/index/ECX . 0/r32/AL 0xc/disp8 . # copy AL to *(EDI+ECX+12) - # ++f->write - ff 0/subop/increment 0/mod/indirect 7/rm32/EDI . . . . . . # increment *EDI -$append-byte:end: - # . restore registers - 5f/pop-to-EDI - 59/pop-to-ECX - # . epilog - 89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP - 5d/pop-to-EBP - c3/return - -$append-byte:abort: - # . _write(2/stderr, error) - # . . push args - 68/push "append-byte: out of space\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-append-byte-single: - # - check that append-byte writes to first byte of 'file' - # 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 - # append-byte(_test-stream, 'A') - # . . push args - 68/push 0x41/imm32 - 68/push _test-stream/imm32 - # . . call - e8/call append-byte/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP - # check-stream-equal(_test-stream, "A", msg) - # . . push args - 68/push "F - test-append-byte-single"/imm32 - 68/push "A"/imm32 - 68/push _test-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 |