include/asm-m68k/delay.h

   1 #ifndef _M68K_DELAY_H
   2 #define _M68K_DELAY_H
   3
   4 #include <asm/param.h>
   5
   6 /*
   7  * Copyright (C) 1994 Hamish Macdonald
   8  *
   9  * Delay routines, using a pre-computed "loops_per_jiffy" value.
  10  */
  11
  12 static inline void __delay(unsigned long loops)
  13 {
  14         __asm__ __volatile__ ("1: subql #1,%0; jcc 1b"
  15                 : "=d" (loops) : "0" (loops));
  16 }
  17
  18 extern void __bad_udelay(void);
  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 static inline void __const_udelay(unsigned long xloops)
  28 {
  29         unsigned long tmp;
  30
  31         __asm__ ("mulul %2,%0:%1"
  32                 : "=d" (xloops), "=d" (tmp)
  33                 : "d" (xloops), "1" (loops_per_jiffy));
  34         __delay(xloops * HZ);
  35 }
  36
  37 static inline void __udelay(unsigned long usecs)
  38 {
  39         __const_udelay(usecs * 4295);   /* 2**32 / 1000000 */
  40 }
  41
  42 #define udelay(n) (__builtin_constant_p(n) ? \
  43         ((n) > 20000 ? __bad_udelay() : __const_udelay((n) * 4295)) : \
  44         __udelay(n))
  45
  46 static inline unsigned long muldiv(unsigned long a, unsigned long b,
  47                                    unsigned long c)
  48 {
  49         unsigned long tmp;
  50
  51         __asm__ ("mulul %2,%0:%1; divul %3,%0:%1"
  52                 : "=d" (tmp), "=d" (a)
  53                 : "d" (b), "d" (c), "1" (a));
  54         return a;
  55 }
  56
  57 #endif /* defined(_M68K_DELAY_H) */