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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * include/asm-v850/delay.h -- Delay routines, using a pre-computed
3 * "loops_per_second" value
4 *
5 * Copyright (C) 2001,03 NEC Corporation
6 * Copyright (C) 2001,03 Miles Bader <miles@gnu.org>
7 * Copyright (C) 1994 Hamish Macdonald
8 *
9 * This file is subject to the terms and conditions of the GNU General
10 * Public License. See the file COPYING in the main directory of this
11 * archive for more details.
12 */
13
14#ifndef __V850_DELAY_H__
15#define __V850_DELAY_H__
16
17#include <asm/param.h>
18
19extern __inline__ void __delay(unsigned long loops)
20{
21 if (loops)
22 __asm__ __volatile__ ("1: add -1, %0; bnz 1b"
23 : "=r" (loops) : "0" (loops));
24}
25
26/*
27 * Use only for very small delays ( < 1 msec). Should probably use a
28 * lookup table, really, as the multiplications take much too long with
29 * short delays. This is a "reasonable" implementation, though (and the
30 * first constant multiplications gets optimized away if the delay is
31 * a constant)
32 */
33
34extern unsigned long loops_per_jiffy;
35
36extern __inline__ void udelay(unsigned long usecs)
37{
38 register unsigned long full_loops, part_loops;
39
40 full_loops = ((usecs * HZ) / 1000000) * loops_per_jiffy;
41 usecs %= (1000000 / HZ);
42 part_loops = (usecs * HZ * loops_per_jiffy) / 1000000;
43
44 __delay(full_loops + part_loops);
45}
46
47#endif /* __V850_DELAY_H__ */