Revision c420bc9f09a0926b708c3edb27eacba434a4f4ba authored by Linus Torvalds on 26 May 2007, 02:55:14 UTC, committed by Linus Torvalds on 26 May 2007, 02:55:14 UTC
It's that time of the year again.  Summer starts in the US, and people
want to sit at the beach with a new -rc candidate.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent f4d43bd
Raw File
int_sqrt.c

#include <linux/kernel.h>
#include <linux/module.h>

/**
 * int_sqrt - rough approximation to sqrt
 * @x: integer of which to calculate the sqrt
 *
 * A very rough approximation to the sqrt() function.
 */
unsigned long int_sqrt(unsigned long x)
{
	unsigned long op, res, one;

	op = x;
	res = 0;

	one = 1UL << (BITS_PER_LONG - 2);
	while (one > op)
		one >>= 2;

	while (one != 0) {
		if (op >= res + one) {
			op = op - (res + one);
			res = res +  2 * one;
		}
		res /= 2;
		one /= 4;
	}
	return res;
}
EXPORT_SYMBOL(int_sqrt);
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