[net-next-2.6.git] / lib / 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);
Commit	Line	Data
1da177e4 LT	1
	2	#include <linux/kernel.h>
	3	#include <linux/module.h>
	4
	5	/**
	6	* int_sqrt - rough approximation to sqrt
	7	* @x: integer of which to calculate the sqrt
	8	*
	9	* A very rough approximation to the sqrt() function.
	10	*/
	11	unsigned long int_sqrt(unsigned long x)
	12	{
	13	unsigned long op, res, one;
	14
	15	op = x;
	16	res = 0;
	17
f0c00257	18	one = 1UL << (BITS_PER_LONG - 2);
1da177e4 LT	19	while (one > op)
	20	one >>= 2;
	21
	22	while (one != 0) {
	23	if (op >= res + one) {
	24	op = op - (res + one);
	25	res = res + 2 * one;
	26	}
	27	res /= 2;
	28	one /= 4;
	29	}
	30	return res;
	31	}
	32	EXPORT_SYMBOL(int_sqrt);