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22 lines
401 B
ArmAsm

;
; Ullrich von Bassewitz, 25.10.2000
;
; CC65 runtime: Increment the stackpointer by value in y
;
.export addysp1, addysp
.importzp sp
addysp1:
iny
addysp: pha ; Save A
clc
tya ; Get the value
adc sp ; Add low byte
sta sp ; Put it back
bcc @L1 ; If no carry, we're done
inc sp+1 ; Inc high byte
@L1: pla ; Restore A
rts