diff options
Diffstat (limited to 'subx/074print-int-decimal.subx')
| -rw-r--r-- | subx/074print-int-decimal.subx | 32 |
1 files changed, 20 insertions, 12 deletions
diff --git a/subx/074print-int-decimal.subx b/subx/074print-int-decimal.subx index a3f9bf9e..7f9dadc5 100644 --- a/subx/074print-int-decimal.subx +++ b/subx/074print-int-decimal.subx @@ -25,11 +25,15 @@ print-int32-decimal: # out : (address stream), n : int32 # if (EAX == 0) break # if n < 0 # push '-' + # w = out->write + # curr = &out->data[out->write] # while true # pop into EAX # if (EAX == sentinel) break - # out->data[out->write] = AL - # ++out->write + # *curr = AL + # ++curr + # ++w + # out->write = w # (based on K&R itoa: https://en.wikibooks.org/wiki/C_Programming/stdlib.h/itoa) # (this pseudocode contains registers because operations like division # require specific registers in x86) @@ -47,7 +51,7 @@ print-int32-decimal: # out : (address stream), n : int32 # push sentinel 68/push 0/imm32/sentinel # EAX = abs(n) - 8b/copy 1/mod/*+disp8 5/rm32/EBP . . . 0/r32/EAX 0xc/disp8 . # EAX = *(EBP+12) + 8b/copy 1/mod/*+disp8 5/rm32/EBP . . . 0/r32/EAX 0xc/disp8 . # copy *(EBP+12) to EAX 3d/compare-EAX-with 0/imm32 7d/jump-if-greater-or-equal $print-int32-decimal:read-loop/disp8 f7 3/subop/negate 3/mod/direct 0/rm32/EAX . . . . . . # negate EAX @@ -70,22 +74,26 @@ $print-int32-decimal:read-break: $print-int32-decimal:write: # EDI = out 8b/copy 1/mod/*+disp8 5/rm32/EBP . . . 7/r32/EDI 8/disp8 . # copy *(EBP+8) to EDI + # w/EDX = out->write + 8b/copy 0/mod/indirect 7/rm32/EDI . . . 2/r32/EDX . . # copy *EDI to EDX + # curr/ECX = &out->data[out->write] + 8d/copy-address 1/mod/*+disp8 4/rm32/sib 7/base/EDI 2/index/EDX . 1/r32/ECX 0xc/disp8 . # copy EBX+EDX+12 to ECX $print-int32-decimal:write-loop: # pop into EAX 58/pop-to-EAX # if (EAX == sentinel) break 3d/compare-EAX-and 0/imm32/sentinel - 74/jump-if-equal $print-int32-decimal:end/disp8 - # out->data[out->write] = AL - # . ECX = out->write - 8b/copy 0/mod/indirect 7/rm32/EDI . . . 1/r32/ECX . . # copy *EDI to ECX - # . ECX = &out->data[out->write] - 8d/copy-address 1/mod/*+disp8 4/rm32/sib 7/base/EDI 1/index/ECX . 1/r32/ECX 0xc/disp8 . # copy EBX+ECX+12 to ECX - # . out->data[out->write] = AL + 74/jump-if-equal $print-int32-decimal:write-break/disp8 + # *curr = AL 88/copy-byte 0/mod/indirect 1/rm32/ECX . . . 0/r32/AL . . # copy AL to byte at *ECX - # out->write++ - ff 0/subop/increment 0/mod/indirect 7/rm32/EDI . . . . . . # increment *EDI + # ++curr + 41/increment-ECX + # ++w + 42/increment-EDX eb/jump $print-int32-decimal:write-loop/disp8 +$print-int32-decimal:write-break: + # out->write = w + 89/copy 0/mod/indirect 7/rm32/EDI . . . 2/r32/EDX . . # copy EDX to *EDI $print-int32-decimal:end: # . restore registers 5f/pop-to-EDI |