summaryrefslogtreecommitdiff
path: root/agbx/source/gfx/flip.s
blob: 019289dd54bc7dd9562233e4b313dd6fd2aa46b4 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
@ Copyright 2022 Gabriel Jensen.
@ This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
@ If a copy of the MPL was not distributed with this file, You can obtain one at https://mozilla.org/MPL/2.0/.

.syntax unified

.cpu arm7tdmi
.thumb

.extern __agbx_getvbnk

.globl agbx_flip

.func

.thumb_func

agbx_flip:
	@ Get the current value of dispcnt:
	ldr r0,.dispcntaddr
	ldrh r1,[r0]

	@ XOR bit five:
	movs r2,0b10000
	eors r1,r2

	@ Save dispcnt:
	strh r1,[r0]

	@ Get the address of the video bank:
	b __agbx_getvbnk
	
	bx lr

.endfunc

.align

.dispcntaddr:
	.long 0x4000000