blob: e16724fdf807bf6b76a87c0d39a56e8ecc5c9afa (
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
|
@ 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
.globl ax_vsync
.func
.thumb_func
ax_vsync:
@ Set the constants:
ldr r0,.vcountaddr @ ax_i02 vcountaddr = 0x4000006u;
movs r1,0xA0 @ ax_i02 numhline = 0xA0;
.loop:
@ Check the scanline counter:
ldrh r2,[r0] @ ax_i02 vcount = *(ax_i01 *)vcountaddr;
cmp r2,r1
beq .ret @ if (vcount == numhline) {goto ret;}
b .loop @ goto loop;
.ret:
@ Return:
bx lr @ return;
.endfunc
.align
.vcountaddr:
.long 0x4000006
|
