kernel26-2.6.12-alx-r9/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 = 1 << 30;
	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);
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
18	one = 1 << 30;
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);