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author | Andrey Smirnov <andrew.smirnov@gmail.com> | 2016-06-27 21:27:58 -0700 |
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committer | Sascha Hauer <s.hauer@pengutronix.de> | 2016-06-30 08:33:53 +0200 |
commit | aa750244ee3dd31abb4888c83bfe65249365717a (patch) | |
tree | 9417339b72970f6ab7ed01f4159c15f99d1f0cc7 /lib/int_sqrt.c | |
parent | 927176bc16aa2d321e7e98dd9f01a6e2004c5001 (diff) | |
download | barebox-aa750244ee3dd31abb4888c83bfe65249365717a.tar.gz barebox-aa750244ee3dd31abb4888c83bfe65249365717a.tar.xz |
video/edid: Move int_sqrt() out
Move int_sqrt() out of drivers/video/edid.c so that it is availible to
other parts of Barebox.
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'lib/int_sqrt.c')
-rw-r--r-- | lib/int_sqrt.c | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/lib/int_sqrt.c b/lib/int_sqrt.c new file mode 100644 index 0000000000..30ccafbf9e --- /dev/null +++ b/lib/int_sqrt.c @@ -0,0 +1,46 @@ +/* + * See file CREDITS for list of people who contributed to this + * project. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ + +#include <common.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 b, m, y = 0; + + if (x <= 1) + return x; + + m = 1UL << (BITS_PER_LONG - 2); + while (m != 0) { + b = y + m; + y >>= 1; + + if (x >= b) { + x -= b; + y += m; + } + m >>= 2; + } + + return y; +} +EXPORT_SYMBOL(int_sqrt); |