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| author | Kartik Agaram <vc@akkartik.com> | 2019-05-04 14:58:13 -0700 |
|---|---|---|
| committer | Kartik Agaram <vc@akkartik.com> | 2019-05-04 14:58:13 -0700 |
| commit | d36c42fa3ff4d6f2f4282bde3c586c67fdacda46 (patch) | |
| tree | a1d8a6ff4befa4a6592f5de20fdc5c94527e1da4 /subx | |
| parent | 8591331a7f674d71c50ea0f560e1412d56001801 (diff) | |
| download | mu-d36c42fa3ff4d6f2f4282bde3c586c67fdacda46.tar.gz | |
5144
Pull in some final stylistic and debugging-friendly tweaks from my old version of commit 5132 and earlier.
Diffstat (limited to 'subx')
| -rw-r--r-- | subx/074print-int-decimal.subx | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/subx/074print-int-decimal.subx b/subx/074print-int-decimal.subx index c6f4951c..04385795 100644 --- a/subx/074print-int-decimal.subx +++ b/subx/074print-int-decimal.subx @@ -14,6 +14,9 @@ #? cd/syscall 0x80/imm8 print-int32-decimal: # out : (address stream), n : int32 + # works by generating characters from lowest to highest and pushing them + # to the stack, before popping them one by one into the stream + # # pseudocode: # push sentinel # EAX = abs(n) @@ -57,7 +60,8 @@ print-int32-decimal: # out : (address stream), n : int32 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 $print-int32-decimal:read-loop/disp8 - f7 3/subop/negate 3/mod/direct 0/rm32/EAX . . . . . . # negate EAX +$print-int32-decimal:negative: + f7 3/subop/negate 3/mod/direct 0/rm32/EAX . . . . . . # negate EAX $print-int32-decimal:read-loop: # EAX, EDX = EAX / 10, EAX % 10 99/sign-extend-EAX-into-EDX @@ -73,6 +77,7 @@ $print-int32-decimal:read-break: # if (n < 0) push('-') 81 7/subop/compare 1/mod/*+disp8 5/rm32/EBP . . . . 0xc/disp8 0/imm32 # compare *(EBP+12) 7d/jump-if-greater-or-equal $print-int32-decimal:write/disp8 +$print-int32-decimal:push-negative: 68/push 0x2d/imm32/- $print-int32-decimal:write: # EDI = out @@ -93,6 +98,7 @@ $print-int32-decimal:write-loop: # if (curr >= max) abort 39/compare 3/mod/direct 1/rm32/ECX . . . 3/r32/EBX . . # compare ECX with EBX 7d/jump-if-greater-or-equal $print-int32-decimal:abort/disp8 +$print-int32-decimal:write-char: # *curr = AL 88/copy-byte 0/mod/indirect 1/rm32/ECX . . . 0/r32/AL . . # copy AL to byte at *ECX # ++curr |