diff options
Diffstat (limited to 'baremetal/115write-byte.subx')
| -rw-r--r-- | baremetal/115write-byte.subx | 82 |
1 files changed, 0 insertions, 82 deletions
diff --git a/baremetal/115write-byte.subx b/baremetal/115write-byte.subx deleted file mode 100644 index 6935d65b..00000000 --- a/baremetal/115write-byte.subx +++ /dev/null @@ -1,82 +0,0 @@ -# Write a single byte to a stream. -# -# We need to do this in machine code because streams need to be opaque types, -# and we don't yet support opaque types in Mu. - -== 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'. -append-byte: # f: (addr stream byte), n: int - # . 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 - 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->size) abort - 3b/compare 1/mod/*+disp8 7/rm32/edi . . . 1/r32/ecx 8/disp8 . # compare ecx with *(edi+8) - 7d/jump-if->= $append-byte:abort/disp8 -$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 -$append-byte:end: - # . restore registers - 5f/pop-to-edi - 59/pop-to-ecx - 58/pop-to-eax - # . epilogue - 89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp - 5d/pop-to-ebp - c3/return - -$append-byte:abort: - (draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0 "append-byte: out of space\n" 3 0) # 3=cyan - { - eb/jump loop/disp8 - } - # 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 |