mirror of
https://github.com/cc65/cc65.git
synced 2024-07-05 06:28:57 +00:00
40 lines
927 B
ArmAsm
40 lines
927 B
ArmAsm
;
|
|
; 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 tosmodeax
|
|
.import poplsargs, udiv32, negeax
|
|
.importzp sreg, ptr1, ptr2, tmp1, tmp3, tmp4
|
|
|
|
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
|
|
|