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38 lines
1002 B
ArmAsm
38 lines
1002 B
ArmAsm
;
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; Ullrich von Bassewitz, 07.08.1998
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; CC65 runtime: division for 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 tosdiva0, tosdivax
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.import popsargs, udiv16, negax
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.importzp sreg, tmp1, tmp2
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tosdiva0:
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ldx #0
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tosdivax:
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jsr popsargs ; Get arguments from stack, adjust sign
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jsr udiv16 ; Do the division
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ldx sreg+1 ; Load high byte of result
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; Adjust the sign of the result. tmp1 contains the high byte of the left
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; operand, tmp2 contains the high byte of the right operand.
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lda tmp1
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eor tmp2
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bpl Pos ; Jump if sign of result positive
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; Result is negative
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lda sreg ; Load low byte of result
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jmp negax ; Adjust the sign
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; Result is positive
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Pos: lda sreg
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rts
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