57e4978eac
Port some support for unicode to baremetal.
38 lines
2.4 KiB
Plaintext
38 lines
2.4 KiB
Plaintext
# 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
|
|
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:end/disp8 # TODO: abort
|
|
$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
|
|
# . epilogue
|
|
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
|