delay.S revision 96cf5185a95e0b304596fe19edcf8dfcd5c10699 
1/*
2 * linux/arch/unicore32/lib/delay.S
3 *
4 * Code specific to PKUnity SoC and UniCore ISA
5 *
6 * Copyright (C) 2001-2010 GUAN Xue-tao
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12#include <linux/linkage.h>
13#include <asm/assembler.h>
14#include <asm/param.h>
15		.text
16
17.LC0:		.word	loops_per_jiffy
18.LC1:		.word	(2199023*HZ)>>11
19
20/*
21 * r0  <= 2000
22 * lpj <= 0x01ffffff (max. 3355 bogomips)
23 * HZ  <= 1000
24 */
25
26ENTRY(__udelay)
27		ldw	r2, .LC1
28		mul	r0, r2, r0
29ENTRY(__const_udelay)				@ 0 <= r0 <= 0x7fffff06
30		ldw	r2, .LC0
31		ldw	r2, [r2]		@ max = 0x01ffffff
32		mov	r0, r0 >> #14		@ max = 0x0001ffff
33		mov	r2, r2 >> #10		@ max = 0x00007fff
34		mul	r0, r2, r0		@ max = 2^32-1
35		mov.a	r0, r0 >> #6
36		cmoveq	pc, lr
37
38/*
39 * loops = r0 * HZ * loops_per_jiffy / 1000000
40 *
41 * Oh, if only we had a cycle counter...
42 */
43
44@ Delay routine
45ENTRY(__delay)
46		sub.a	r0, r0, #2
47		bua	__delay
48		mov	pc, lr
49ENDPROC(__udelay)
50ENDPROC(__const_udelay)
51ENDPROC(__delay)
52