diff options
Diffstat (limited to 'subx/068new-stream.subx')
| -rw-r--r-- | subx/068new-stream.subx | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/subx/068new-stream.subx b/subx/068new-stream.subx new file mode 100644 index 00000000..2020229d --- /dev/null +++ b/subx/068new-stream.subx @@ -0,0 +1,126 @@ +# Helper to allocate a stream on the heap. +# +# We'll now start gingerly supporting streams containing arbitrary types. + +== 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 + +# main: + e8/call run-tests/disp32 # 'run-tests' is a function created automatically by SubX. It calls all functions that start with 'test-'. + # 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 + +new-stream: # ad : (address allocation-descriptor), length : int, elemsize : int -> address/EAX + # . prolog + 55/push-EBP + 89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP + # . save registers + 52/push-EDX + # n = elemsize * length + 12 (for read, write and length) + # . EAX = elemsize + 8b/copy 1/mod/*+disp8 5/rm32/EBP . . . 0/r32/EAX 0x10/disp8 . # copy *(EBP+16) to EAX + # . EAX *= length + 31/xor 3/mod/direct 2/rm32/EDX . . . 2/r32/EDX . . # clear EDX + f7 4/subop/multiply 1/mod/*+disp8 5/rm32/EBP . . 0xc/disp8 . # multiply *(EBP+12) into EAX + # . if overflow abort + 81 7/subop/compare 3/mod/direct 2/rm32/EDX . . . . . 0/imm32 # compare EDX + 75/jump-if-not-equal $new-stream:abort/disp8 + # . EDX = elemsize*length + 89/copy 3/mod/direct 2/rm32/EDX . . . 0/r32/EAX . . # copy EAX to EDX + # . EAX += 12 + 05/add-to-EAX 0xc/imm32 + # allocate(ad, n) + # . . push args + 50/push-EAX + ff 6/subop/push 1/mod/*+disp8 5/rm32/EBP . . . . 8/disp8 . # push *(EBP+8) + # . . call + e8/call allocate/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP + # EAX->length = elemsize*length + 89/copy 1/mod/*+disp8 0/rm32/EAX . . . 2/r32/EDX 8/disp8 . # copy EDX to *(EAX+8) + # clear-stream(EAX) + # . . push args + 50/push-EAX + # . . call + e8/call clear-stream/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add to ESP +$new-stream:end: + # . restore registers + 5a/pop-to-EDX + # . epilog + 89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP + 5d/pop-to-EBP + c3/return + +$new-stream:abort: + # . _write(2/stderr, error) + # . . push args + 68/push "new-stream: size too large"/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-new-stream: + # . prolog + 55/push-EBP + 89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP + # var ad/ECX : (address allocation-descriptor) = allocate-region(Heap, 512) + # . EAX = allocate-region(Heap, 512) + # . . push args + 68/push 0x200/imm32 + 68/push Heap/imm32 + # . . call + e8/call allocate-region/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP + # . ECX = EAX + 89/copy 3/mod/direct 1/rm32/ECX . . . 0/r32/EAX . . # copy EAX to ECX + # var start/EDX = ad->curr + 8b/copy 0/mod/indirect 1/rm32/ECX . . . 2/r32/EDX . . # copy *ECX to EDX + # EAX = new-stream(ad, 3, 2) + # . . push args + 68/push 2/imm32 + 68/push 3/imm32 + 51/push-ECX + # . . call + e8/call new-stream/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP + # check-ints-equal(EAX, EDX, msg) + # . . push args + 68/push "F - test-new-stream: returns current pointer of allocation descriptor"/imm32 + 52/push-EDX + 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-ints-equal(EAX->length, 6, msg) + # . . push args + 68/push "F - test-new-stream: sets length correctly"/imm32 + 68/push 6/imm32 + ff 6/subop/push 1/mod/*+disp8 0/rm32/EAX . . . . . 8/disp8 # push *(EAX+8) + # . . call + e8/call check-ints-equal/disp32 + # . . discard args + 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP + # the rest is delegated to clear-stream() so we won't bother checking it + # . epilog + 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 |