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cc65/libsrc/runtime/add.s
cuz b4163d0e4e Added some 65C02 code.
git-svn-id: svn://svn.cc65.org/cc65/trunk@484 b7a2c559-68d2-44c3-8de9-860c34a00d81
2000-11-27 22:59:03 +00:00

38 lines
534 B
ArmAsm

;
; 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