delay.h

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#ifndef _LINUX_DELAY_H
#define _LINUX_DELAY_H

/**
*

 * Copyright (C) 1993 Linus Torvalds
 *
 * Delay routines, using a pre-computed "loops_per_second" value.


*/

extern unsigned long loops_per_sec;

extern __inline__ void __delay(int loops)
{
        __asm__(".align 2,0x90\n1:\tdecl %0\n\tjns 1b": :"a" (loops):"ax");
}

/**
*

 * division by multiplication: you don't have to worry about
 * loss of precision.
 *
 * Use only for very small delays ( < 1 msec).  Should probably use a
 * lookup table, really, as the multiplications take much too long with
 * short delays.  This is a "reasonable" implementation, though (and the
 * first constant multiplications gets optimized away if the delay is
 * a constant)


*/
extern __inline__ void udelay(unsigned long usecs)
{
        usecs *= 0x000010c6;            ///< 2**32 / 1000000 
        __asm__("mull %0"
                :"=d" (usecs)
                :"a" (usecs),"0" (loops_per_sec)
                :"ax");
        __delay(usecs);
}

#endif

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