mirror of
https://github.com/cc65/cc65.git
synced 2024-12-25 02:29:52 +00:00
38 lines
932 B
ArmAsm
38 lines
932 B
ArmAsm
;
|
|
; Ullrich von Bassewitz, 07.08.1998
|
|
;
|
|
; CC65 runtime: division for 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 tosdiva0, tosdivax
|
|
.import popsargs, udiv16, negax
|
|
.importzp sreg, tmp1, tmp2
|
|
|
|
tosdiva0:
|
|
ldx #0
|
|
tosdivax:
|
|
jsr popsargs ; Get arguments from stack, adjust sign
|
|
jsr udiv16 ; Do the division
|
|
ldx sreg+1 ; Load high byte of result
|
|
|
|
; Adjust the sign of the result. tmp1 contains the high byte of the left
|
|
; operand, tmp2 contains the high byte of the right operand.
|
|
|
|
lda tmp1
|
|
eor tmp2
|
|
bpl Pos ; Jump if sign of result positive
|
|
|
|
; Result is negative
|
|
|
|
lda sreg ; Load low byte of result
|
|
jmp negax ; Adjust the sign
|
|
|
|
; Result is positive
|
|
|
|
Pos: lda sreg
|
|
rts
|
|
|