; ; Ullrich von Bassewitz, 07.08.1998 ; ; CC65 runtime: modulo operation for long 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 tosmod0ax, tosmodeax .import poplsargs, udiv32, negeax .importzp sreg, ptr1, ptr2, tmp1, tmp3, tmp4 tosmod0ax: ldy #$00 sty sreg sty sreg+1 tosmodeax: jsr poplsargs ; Get arguments from stack, adjust sign jsr udiv32 ; Do the division, remainder is in (ptr2:tmp3:tmp4) ; Load the result lda ptr2 ldx ptr2+1 ldy tmp3 sty sreg ldy tmp4 sty sreg+1 ; Check the sign of the result. It is the sign of the left operand. bit tmp1 ; Check sign of left operand bpl Pos ; Jump if result is positive ; Result is negative jmp negeax ; Negate result ; Result is positive Pos: rts ; Done