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/*
* Copyright (C) 2013 Davidlohr Bueso <davidlohr.bueso@hp.com>
*
* Based on the shift-and-subtract algorithm for computing integer
* square root from Guy L. Steele.
*/
#include <linux/kernel.h>
#include <linux/export.h>
/**
* int_sqrt - rough approximation to sqrt
* @x: integer of which to calculate the sqrt
*
* A very rough approximation to the sqrt() function.
*/
inline unsigned long int_sqrt(unsigned long x)
{
register unsigned long tmp;
register unsigned long place;
register unsigned long root = 0;
if (x <= 1)
return x;
place = 1UL << (BITS_PER_LONG - 2);
do{
place >>= 2;
}while(place > x);
do {
tmp = root + place;
root >>= 1;
if (x >= tmp)
{
x -= tmp;
root += place;
}
place >>= 2;
}while (place != 0);
return root;
}
EXPORT_SYMBOL(int_sqrt);
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