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>

2 files changed, 47 insertions, 0 deletions

diff --git a/lib/Makefile b/lib/Makefile
index 399d896bd9..92404fd331 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -58,3 +58,4 @@ obj-$(CONFIG_BAREBOX_LOGO)     += logo/
 obj-y			+= reed_solomon/
 obj-$(CONFIG_RATP)	+= ratp.o
 obj-y			+= list_sort.o
+obj-y			+= int_sqrt.o
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);