26 lines
304 B
ArmAsm
26 lines
304 B
ArmAsm
.include "global.s"
|
|
|
|
;; BANKED: checked, imperfect
|
|
.area _BASE
|
|
|
|
_scroll_bkg::
|
|
LDA HL,2(SP) ; Skip return address
|
|
XOR A
|
|
CP (HL) ; Is x != 0
|
|
JR Z,1$
|
|
|
|
LDH A,(.SCX) ; Yes
|
|
ADD (HL)
|
|
LDH (.SCX),A
|
|
1$:
|
|
INC HL
|
|
XOR A
|
|
CP (HL) ; Is y != 0
|
|
JR Z,2$
|
|
|
|
LDH A,(.SCY) ; Yes
|
|
ADD (HL)
|
|
LDH (.SCY),A
|
|
2$:
|
|
RET
|