ia64/linux-2.6.18-xen.hg

view lib/int_sqrt.c @ 0:831230e53067

Import 2.6.18 from kernel.org tarball.
author Ian Campbell <ian.campbell@xensource.com>
date Wed Apr 11 14:15:44 2007 +0100 (2007-04-11)
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2 #include <linux/kernel.h>
3 #include <linux/module.h>
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;
15 op = x;
16 res = 0;
18 one = 1UL << (BITS_PER_LONG - 2);
19 while (one > op)
20 one >>= 2;
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);