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woz64/math.asm
2019-11-16 23:41:00 -08:00

31 lines
620 B
NASM

#importonce
.filenamespace Math
#import "mem_map.asm"
* = * "Math Routines"
multiply: {
stx MemMap.MATH.multiTmpX
pha
lda #$00
ldx #$08
clc
m0: bcc.r m1
clc
adc MemMap.MATH.factor2
m1: ror
ror MemMap.MATH.factor1
dex
bpl.r m0
ldx MemMap.MATH.factor1
sta MemMap.MATH.result
stx MemMap.MATH.result+1
pla
ldx MemMap.MATH.multiTmpX
rts
}