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5144 

Pull in some final stylistic and debugging-friendly tweaks from my old
version of commit 5132 and earlier.
This commit is contained in:
Kartik Agaram 2019-05-04 14:58:13 -07:00
parent 8591331a7f
commit d36c42fa3f
1 changed files with 7 additions and 1 deletions
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8
subx/074print-int-decimal.subx
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@ -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