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/* $Id: delay.h,v 1.2 1999/01/04 16:09:20 ralf Exp $
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1994 by Waldorf Electronics
* Copyright (C) 1995 - 1998 by Ralf Baechle
*/
#ifndef _ASM_DELAY_H
#define _ASM_DELAY_H
extern __inline__ void
__delay(unsigned long loops)
{
__asm__ __volatile__ (
".set\tnoreorder\n"
"1:\tbnez\t%0,1b\n\t"
"subu\t%0,1\n\t"
".set\treorder"
:"=r" (loops)
:"0" (loops));
}
/*
* division by multiplication: you don't have to worry about
* loss of precision.
*
* Use only for very small delays ( < 1 msec). Should probably use a
* lookup table, really, as the multiplications take much too long with
* short delays. This is a "reasonable" implementation, though (and the
* first constant multiplications gets optimized away if the delay is
* a constant)
*/
extern __inline__ void __udelay(unsigned long usecs, unsigned long lps)
{
usecs *= 0x000010c6; /* 2**32 / 1000000 */
__asm__("multu\t%0,%2\n\t"
"mfhi\t%0"
:"=r" (usecs)
:"0" (usecs),"r" (lps));
__delay(usecs);
}
#ifdef __SMP__
#define __udelay_val cpu_data[smp_processor_id()].udelay_val
#else
#define __udelay_val loops_per_sec
#endif
#define udelay(usecs) __udelay((usecs),__udelay_val)
#endif /* _ASM_DELAY_H */
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