Revision baca2da4c9c5de63b215b1d82f8e774449d15655 authored by Russell King on 04 June 2006, 16:36:31 UTC, committed by Russell King on 04 June 2006, 16:36:31 UTC
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
1 parent 672c610
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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