39 lines
509 B
ArmAsm
39 lines
509 B
ArmAsm
.define Mli4
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.sect .text
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.sect .rom
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.sect .data
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.sect .bss
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.sect .text
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! This subroutine multiplies two signed fourbyte integers
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! For more detail see mli.s
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! The only difference is that zeropage locations are twice as big.
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Mli4:
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ldy #1
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sty UNSIGN
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jsr Pop
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stx ARTH
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sta ARTH+1
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jsr Pop
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stx ARTH+2
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sta ARTH+3 ! multiplier
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jsr Pop
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stx ARTH+4
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sta ARTH+5
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jsr Pop
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stx ARTH+6
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sta ARTH+7 ! multiplicand
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lda ARTH+3
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bpl 3f
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lda #0
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ldx #ARTH
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jsr Ngi4
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lda #0
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ldx #ARTH+4
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jsr Ngi4
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3: jmp Mul4
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