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/*
* 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 - 2000, 01, 03 by Ralf Baechle
* Copyright (C) 1999, 2000 Silicon Graphics, Inc.
*/
#ifndef _ASM_DELAY_H
#define _ASM_DELAY_H
#include <linux/config.h>
#include <linux/param.h>
#include <linux/smp.h>
#include <asm/compiler.h>
static inline void __delay(unsigned long loops)
{
if (sizeof(long) == 4)
__asm__ __volatile__ (
".set\tnoreorder\n"
"1:\tbnez\t%0,1b\n\t"
"subu\t%0,1\n\t"
".set\treorder"
: "=r" (loops)
: "0" (loops));
else if (sizeof(long) == 8)
__asm__ __volatile__ (
".set\tnoreorder\n"
"1:\tbnez\t%0,1b\n\t"
"dsubu\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)
*/
static inline void __udelay(unsigned long usecs, unsigned long lpj)
{
unsigned long lo;
/*
* The common rates of 1000 and 128 are rounded wrongly by the
* catchall case for 64-bit. Excessive precission? Probably ...
*/
#if defined(CONFIG_64BIT) && (HZ == 128)
usecs *= 0x0008637bd05af6c7UL; /* 2**64 / (1000000 / HZ) */
#elif defined(CONFIG_64BIT) && (HZ == 1000)
usecs *= 0x004189374BC6A7f0UL; /* 2**64 / (1000000 / HZ) */
#elif defined(CONFIG_64BIT)
usecs *= (0x8000000000000000UL / (500000 / HZ));
#else /* 32-bit junk follows here */
usecs *= (unsigned long) (((0x8000000000000000ULL / (500000 / HZ)) +
0x80000000ULL) >> 32);
#endif
if (sizeof(long) == 4)
__asm__("multu\t%2, %3"
: "=h" (usecs), "=l" (lo)
: "r" (usecs), "r" (lpj)
: GCC_REG_ACCUM);
else if (sizeof(long) == 8)
__asm__("dmultu\t%2, %3"
: "=h" (usecs), "=l" (lo)
: "r" (usecs), "r" (lpj)
: GCC_REG_ACCUM);
__delay(usecs);
}
#define __udelay_val cpu_data[smp_processor_id()].udelay_val
#define udelay(usecs) __udelay((usecs),__udelay_val)
/* make sure "usecs *= ..." in udelay do not overflow. */
#if HZ >= 1000
#define MAX_UDELAY_MS 1
#elif HZ <= 200
#define MAX_UDELAY_MS 5
#else
#define MAX_UDELAY_MS (1000 / HZ)
#endif
#endif /* _ASM_DELAY_H */
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