arch/h8300/include/asm/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 static inline void __delay(unsigned long loops)
  13 {
  14         __asm__ __volatile__ ("1:\n\t"
  15                               "dec.l #1,%0\n\t"
  16                               "bne 1b"
  17                               :"=r" (loops):"0"(loops));
  18 }
  19
  20 /*
  21  * Use only for very small delays ( < 1 msec).  Should probably use a
  22  * lookup table, really, as the multiplications take much too long with
  23  * short delays.  This is a "reasonable" implementation, though (and the
  24  * first constant multiplications gets optimized away if the delay is
  25  * a constant)
  26  */
  27
  28 extern unsigned long loops_per_jiffy;
  29
  30 static inline void udelay(unsigned long usecs)
  31 {
  32         usecs *= 4295;          /* 2**32 / 1000000 */
  33         usecs /= (loops_per_jiffy*HZ);
  34         if (usecs)
  35                 __delay(usecs);
  36 }
  37
  38 #endif /* _H8300_DELAY_H */