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45 lines
1.0 KiB
ArmAsm
45 lines
1.0 KiB
ArmAsm
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; Ullrich von Bassewitz, 07.08.1998
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; CC65 runtime: modulo operation for long signed ints
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;
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; When negating values, we will ignore the possibility here, that one of the
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; values if $8000, in which case the negate will fail.
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.export tosmod0ax, tosmodeax
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.import poplsargs, udiv32, negeax
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.importzp sreg, ptr1, ptr2, tmp1, tmp3, tmp4
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tosmod0ax:
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ldy #$00
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sty sreg
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sty sreg+1
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tosmodeax:
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jsr poplsargs ; Get arguments from stack, adjust sign
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jsr udiv32 ; Do the division, remainder is in (ptr2:tmp3:tmp4)
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; Load the result
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lda ptr2
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ldx ptr2+1
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ldy tmp3
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sty sreg
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ldy tmp4
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sty sreg+1
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; Check the sign of the result. It is the sign of the left operand.
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bit tmp1 ; Check sign of left operand
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bpl Pos ; Jump if result is positive
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; Result is negative
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jmp negeax ; Negate result
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; Result is positive
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Pos: rts ; Done
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