rdtsc_timer.h File Reference

RDTSC timer. More...

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Defines
#define	TIMER_PREFIX_rdtsc   __rdtsc_
#define	TSC_SHIFT   8
	RDTSC values can easily overflow an unsigned long.
Functions
	FILE_LICENCE (GPL2_OR_LATER)
static __always_inline unsigned long	TIMER_INLINE (rdtsc, currticks)(void)
	Get current system time in ticks.

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Detailed Description

RDTSC timer.

Definition in file rdtsc_timer.h.

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Define Documentation

#define TIMER_PREFIX_rdtsc   __rdtsc_

Definition at line 15 of file rdtsc_timer.h.

#define TSC_SHIFT   8

RDTSC values can easily overflow an unsigned long.

We discard the low-order bits in order to obtain sensibly-scaled values.

Definition at line 22 of file rdtsc_timer.h.

Referenced by rdtsc_udelay(), and TIMER_INLINE().

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Function Documentation

FILE_LICENCE

(

GPL2_OR_LATER

)

static __always_inline unsigned long TIMER_INLINE	(	rdtsc	,
		currticks
	)			[inline, static]

Get current system time in ticks.

Return values:

ticks

Current time, in ticks

Definition at line 30 of file rdtsc_timer.h.

References __asm__(), and TSC_SHIFT.

                                           {
        unsigned long ticks;

        __asm__ __volatile__ ( "rdtsc\n\t"
                               "shrdl %1, %%edx, %%eax\n\t"
                               : "=a" ( ticks ) : "i" ( TSC_SHIFT ) : "edx" );
        return ticks;
}