/*

 * Precise Delay Loops for i386

 *

 * Copyright (C) 1993 Linus Torvalds

 * Copyright (C) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>

 *

 * The __delay function must _NOT_ be inlined as its execution time

 * depends wildly on alignment on many x86 processors. The additional

 * jump magic is needed to get the timing stable on all the CPU's

 * we have to worry about.

 */

#include <xen/delay.h>

#include <xen/time.h>

#include <asm/msr.h>

#include <asm/processor.h>

void __udelay(unsigned long usecs)

{

    unsigned long ticks = usecs * (cpu_khz / 1000);

    unsigned long s, e;

    s = rdtsc_ordered();

    do

    {

        rep_nop();

        e = rdtsc_ordered();

    } while ((e-s) < ticks);

}