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/*
* linux/include/asm-i386/timex.h
*
* i386 architecture timex specifications
*/
#ifndef _ASMi386_TIMEX_H
#define _ASMi386_TIMEX_H
#include <linux/config.h>
#define CLOCK_TICK_RATE 1193180 /* Underlying HZ */
#define CLOCK_TICK_FACTOR 20 /* Factor of both 1000000 and CLOCK_TICK_RATE */
#define FINETUNE ((((((long)LATCH * HZ - CLOCK_TICK_RATE) << SHIFT_HZ) * \
(1000000/CLOCK_TICK_FACTOR) / (CLOCK_TICK_RATE/CLOCK_TICK_FACTOR)) \
<< (SHIFT_SCALE-SHIFT_HZ)) / HZ)
/*
* Standard way to access the cycle counter on i586+ CPUs.
* Currently only used on SMP.
*
* If you really have a SMP machine with i486 chips or older,
* compile for that, and this will just always return zero.
* That's ok, it just means that the nicer scheduling heuristics
* won't work for you.
*
* We only use the low 32 bits, and we'd simply better make sure
* that we reschedule before that wraps. Scheduling at least every
* four billion cycles just basically sounds like a good idea,
* regardless of how fast the machine is.
*/
typedef unsigned long cycles_t;
extern cycles_t cacheflush_time;
static inline cycles_t get_cycles (void)
{
#ifndef CONFIG_X86_TSC
return 0;
#else
unsigned long eax, edx;
__asm__("rdtsc":"=a" (eax), "=d" (edx));
return eax;
#endif
}
#endif
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