diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /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.c | 32 |
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 | */ | ||
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); | ||