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41 lines
986 B
ArmAsm
41 lines
986 B
ArmAsm
12 years ago
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; Ullrich von Bassewitz, 17.08.1998
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; CC65 runtime: division for signed long 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 $80000000, in which case the negate will fail.
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.export tosdiv0ax, tosdiveax
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.import poplsargs, udiv32, negeax
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.importzp sreg, ptr1, tmp1, tmp2
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tosdiv0ax:
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ldy #$00
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sty sreg
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sty sreg+1
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tosdiveax:
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jsr poplsargs ; Get arguments from stack, adjust sign
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jsr udiv32 ; Do the division, result is in (ptr1:sreg)
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ldx ptr1+1 ; Load byte 1 of result
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; Adjust the sign of the result
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lda tmp1 ; Get sign of left operand
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eor tmp2 ; Calculate sign of result
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bpl Pos ; Jump if result positive
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; Result is negative
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lda ptr1 ; Load byte 0
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jmp negeax ; Negate value
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; Result is positive
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Pos: lda ptr1
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rts
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