; ; Ullrich von Bassewitz, 07.08.1998 ; ; CC65 runtime: helper stuff for mod/div/mul with signed ints ; ; When negating values, we will ignore the possibility here, that one of the ; values if $8000, in which case the negate will fail. .export popsargs, adjsres .import negax, popax .importzp sreg, tmp1, tmp2, ptr4 popsargs: stx tmp1 ; Remember sign cpx #0 bpl L1 jsr negax ; Negate accumulator L1: sta ptr4 stx ptr4+1 ; Save right operand jsr popax stx tmp2 ; Remember sign cpx #0 bpl L2 jsr negax L2: sta sreg stx sreg+1 ; Calculate the sign of the result, that is sign(op1) * sign(op2) lda tmp1 eor tmp2 sta tmp2 ; Save it across call L3: rts ; Adjust the result of a mod/div/mul operation adjsres: ; Check if we must adjust the sign ldy tmp2 bpl L3 jmp negax ; Adjust sign