delay.h

Go to the documentation of this file.

#ifndef _H8300_DELAY_H
#define _H8300_DELAY_H

#include <asm/param.h>

/*
 * Copyright (C) 2002 Yoshinori Sato <[email protected]>
 *
 * Delay routines, using a pre-computed "loops_per_second" value.
 */

static inline void __delay(unsigned long loops)
{
    __asm__ __volatile__ ("1:\n\t"
                  "dec.l #1,%0\n\t"
                  "bne 1b"
                  :"=r" (loops):"0"(loops));
}

/*
 * 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 unsigned long loops_per_jiffy;

static inline void udelay(unsigned long usecs)
{
    usecs *= 4295;      /* 2**32 / 1000000 */
    usecs /= (loops_per_jiffy*HZ);
    if (usecs)
        __delay(usecs);
}

#endif /* _H8300_DELAY_H */