i386-time.h

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/*
 * Copyright (C) 2002 Luca Abeni, 2003 Luca Marzario
 * This is Free Software; see GPL.txt for details
 */

#ifndef __TIME_H__
#define __TIME_H__

extern unsigned long cpu_khz;
extern unsigned long fast_gettimeoffset_quotient;

static inline long long llimd(long long ll, int mult, int div);

/* fast_gettimeoffset_quotient = 2^32 * (1 / (TSC clocks per usec)) */
static inline unsigned long long int us2clock(unsigned long u)
{
  return llimd(u, cpu_khz, 1000);
}

static inline unsigned long int clock2ms(unsigned long long c)
{
  return (unsigned long int)(llimd(c, fast_gettimeoffset_quotient, 1000) >> 32);
}

static inline unsigned long int clock2us(unsigned long long c)
{
    return  (unsigned long int) ((c * fast_gettimeoffset_quotient) >> 32);
}

static inline unsigned long int clock2jiffies(unsigned long long c)
{
  unsigned long long int tmp;
  
  tmp = (c * fast_gettimeoffset_quotient) >> 32;
  return llimd(tmp, HZ, 1000000);
}

static inline unsigned long int clock2subjiffies(unsigned long long c)
{
  unsigned long long int tmp, tmp1, tmp2;
  
  tmp = (c * fast_gettimeoffset_quotient) >> 32;
  tmp1 = llimd(tmp, HZ, 1000000);
  tmp2 = llimd(tmp1, 1000000, HZ);
  return c - llimd(tmp2, cpu_khz, 1000);
}

static inline unsigned long long sched_read_clock(void)
{
  unsigned long long res;

  __asm__ __volatile__( "rdtsc" : "=A" (res));
  return res;
}
  
static inline unsigned long sched_read_clock_us(void)
{
  return clock2us(sched_read_clock());
}

/* This function comes from RTAI (http://www.rtai.org) */
static inline long long llimd(long long ll, int mult, int div)
{
        __asm__ __volatile (\
                 "movl %%edx,%%ecx; mull %%esi;       movl %%eax,%%ebx;  \n\t"
                 "movl %%ecx,%%eax; movl %%edx,%%ecx; mull %%esi;        \n\t"
                 "addl %%ecx,%%eax; adcl $0,%%edx;    divl %%edi;        \n\t"
                 "movl %%eax,%%ecx; movl %%ebx,%%eax; divl %%edi;        \n\t"
                 "sal $1,%%edx;     cmpl %%edx,%%edi; movl %%ecx,%%edx;  \n\t"
                 "jge 1f;           addl $1,%%eax;    adcl $0,%%edx;     1:"
                 : "=A" (ll)
                 : "A" (ll), "S" (mult), "D" (div)
                 : "%ebx", "%ecx");
        return ll;
}

#endif /* __TIME_H__ */

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