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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /lib/int_sqrt.c
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'lib/int_sqrt.c')
-rw-r--r--lib/int_sqrt.c32
1 files changed, 32 insertions, 0 deletions
diff --git a/lib/int_sqrt.c b/lib/int_sqrt.c
new file mode 100644
index 00000000000..a5d2cdc5684
--- /dev/null
+++ b/lib/int_sqrt.c
@@ -0,0 +1,32 @@
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 */
11unsigned 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}
32EXPORT_SYMBOL(int_sqrt);