include/asm-m68k/delay.h

   1 #ifndef _M68K_DELAY_H
   2 #define _M68K_DELAY_H
   3
   4 /*
   5  * Copyright (C) 1994 Hamish Macdonald
   6  *
   7  * Delay routines, using a pre-computed "loops_per_second" value.
   8  */
   9
  10 extern __inline__ void __delay(unsigned long loops)
  11 {
  12         __asm__ __volatile__ ("1: subql #1,%0; jcc 1b"
  13                 : "=d" (loops) : "0" (loops));
  14 }
  15
  16 /*
  17  * Use only for very small delays ( < 1 msec).  Should probably use a
  18  * lookup table, really, as the multiplications take much too long with
  19  * short delays.  This is a "reasonable" implementation, though (and the
  20  * first constant multiplications gets optimized away if the delay is
  21  * a constant)
  22  */
  23 extern __inline__ void udelay(unsigned long usecs)
  24 {
  25         unsigned long tmp;
  26
  27         usecs *= 4295;          /* 2**32 / 1000000 */
  28         __asm__ ("mulul %2,%0:%1"
  29                 : "=d" (usecs), "=d" (tmp)
  30                 : "d" (usecs), "1" (loops_per_sec));
  31         __delay(usecs);
  32 }
  33
  34 extern __inline__ unsigned long muldiv(unsigned long a, unsigned long b, unsigned long c)
  35 {
  36         unsigned long tmp;
  37
  38         __asm__ ("mulul %2,%0:%1; divul %3,%0:%1"
  39                 : "=d" (tmp), "=d" (a)
  40                 : "d" (b), "d" (c), "1" (a));
  41         return a;
  42 }
  43
  44 #endif /* defined(_M68K_DELAY_H) */