1
0
mirror of https://github.com/cc65/cc65.git synced 2024-07-05 06:28:57 +00:00
cc65/libsrc/runtime/add.s

38 lines
534 B
ArmAsm
Raw Normal View History

;
; Ullrich von Bassewitz, 05.08.1998
;
; CC65 runtime: add ints
;
; Make this as fast as possible, even if it needs more space since it's
; called a lot!
.export tosadda0, tosaddax
.importzp sp
tosadda0:
ldx #0
tosaddax:
clc
.ifpc02
adc (sp) ; 65C02 version - saves 2 cycles
ldy #1
.else
ldy #0
adc (sp),y ; lo byte
iny
.endif
pha ; save it
txa
adc (sp),y ; hi byte
tax
clc
lda sp
adc #2
sta sp
bcc L1
inc sp+1
L1: pla ; Restore low byte
rts