1/*
 2 *  linux/arch/arm/lib/delay.S
 3 *
 4 *  Copyright (C) 1995, 1996 Russell King
 5 *
 6 * This program is free software; you can redistribute it and/or modify
 7 * it under the terms of the GNU General Public License version 2 as
 8 * published by the Free Software Foundation.
 9 */
10#include <linux/linkage.h>
11#include <asm/assembler.h>
12#include <asm/param.h>
13		.text
14
15.LC0:		.word	loops_per_jiffy
16.LC1:		.word	(2199023*HZ)>>11
17
18/*
19 * r0  <= 2000
20 * lpj <= 0x01ffffff (max. 3355 bogomips)
21 * HZ  <= 1000
22 */
23
24ENTRY(__udelay)
25		ldr	r2, .LC1
26		mul	r0, r2, r0
27ENTRY(__const_udelay)				@ 0 <= r0 <= 0x7fffff06
28		mov	r1, #-1
29		ldr	r2, .LC0
30		ldr	r2, [r2]		@ max = 0x01ffffff
31		add	r0, r0, r1, lsr #32-14
32		mov	r0, r0, lsr #14		@ max = 0x0001ffff
33		add	r2, r2, r1, lsr #32-10
34		mov	r2, r2, lsr #10		@ max = 0x00007fff
35		mul	r0, r2, r0		@ max = 2^32-1
36		add	r0, r0, r1, lsr #32-6
37		movs	r0, r0, lsr #6
38		moveq	pc, lr
39
40/*
41 * loops = r0 * HZ * loops_per_jiffy / 1000000
42 *
43 * Oh, if only we had a cycle counter...
44 */
45
46@ Delay routine
47ENTRY(__delay)
48		subs	r0, r0, #1
49#if 0
50		movls	pc, lr
51		subs	r0, r0, #1
52		movls	pc, lr
53		subs	r0, r0, #1
54		movls	pc, lr
55		subs	r0, r0, #1
56		movls	pc, lr
57		subs	r0, r0, #1
58		movls	pc, lr
59		subs	r0, r0, #1
60		movls	pc, lr
61		subs	r0, r0, #1
62		movls	pc, lr
63		subs	r0, r0, #1
64#endif
65		bhi	__delay
66		mov	pc, lr
67ENDPROC(__udelay)
68ENDPROC(__const_udelay)
69ENDPROC(__delay)