tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * linux/arch/unicore32/lib/delay.S
4 *
5 * Code specific to PKUnity SoC and UniCore ISA
6 *
7 * Copyright (C) 2001-2010 GUAN Xue-tao
8 */
9#include <linux/linkage.h>
10#include <asm/assembler.h>
11#include <asm/param.h>
12 .text
13
14.LC0: .word loops_per_jiffy
15.LC1: .word (2199023*HZ)>>11
16
17/*
18 * r0 <= 2000
19 * lpj <= 0x01ffffff (max. 3355 bogomips)
20 * HZ <= 1000
21 */
22
23ENTRY(__udelay)
24 ldw r2, .LC1
25 mul r0, r2, r0
26ENTRY(__const_udelay) @ 0 <= r0 <= 0x7fffff06
27 ldw r2, .LC0
28 ldw r2, [r2] @ max = 0x01ffffff
29 mov r0, r0 >> #14 @ max = 0x0001ffff
30 mov r2, r2 >> #10 @ max = 0x00007fff
31 mul r0, r2, r0 @ max = 2^32-1
32 mov.a r0, r0 >> #6
33 cmoveq pc, lr
34
35/*
36 * loops = r0 * HZ * loops_per_jiffy / 1000000
37 *
38 * Oh, if only we had a cycle counter...
39 */
40
41@ Delay routine
42ENTRY(__delay)
43 sub.a r0, r0, #2
44 bua __delay
45 mov pc, lr
46ENDPROC(__udelay)
47ENDPROC(__const_udelay)
48ENDPROC(__delay)