include/asm-h8300/delay.h

   1 #ifndef _H8300_DELAY_H
   2 #define _H8300_DELAY_H
   3
   4 #include <asm/param.h>
   5
   6 /*
   7  * Copyright (C) 2002 Yoshinori Sato <ysato@sourceforge.jp>
   8  *
   9  * Delay routines, using a pre-computed "loops_per_second" value.
  10  */
  11
  12 extern __inline__ void __delay(unsigned long loops)
  13 {
  14         __asm__ __volatile__ ("mov.l %0,er0\n\t"
  15                               "1:\n\t"
  16                               "dec.l #1,er0\n\t"
  17                               "bne 1b"
  18                               ::"r" (loops):"er0");
  19 }
  20
  21 /*
  22  * Use only for very small delays ( < 1 msec).  Should probably use a
  23  * lookup table, really, as the multiplications take much too long with
  24  * short delays.  This is a "reasonable" implementation, though (and the
  25  * first constant multiplications gets optimized away if the delay is
  26  * a constant)
  27  */
  28
  29 extern unsigned long loops_per_jiffy;
  30
  31 extern __inline__ void udelay(unsigned long usecs)
  32 {
  33         usecs *= 4295;          /* 2**32 / 1000000 */
  34         usecs /= (loops_per_jiffy*HZ);
  35         if (usecs)
  36                 __delay(usecs);
  37 }
  38
  39 #endif /* _H8300_DELAY_H */