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-rw-r--r--digital/avr/modules/math/fixed/fixed_sqrt_ui32.c48
1 files changed, 48 insertions, 0 deletions
diff --git a/digital/avr/modules/math/fixed/fixed_sqrt_ui32.c b/digital/avr/modules/math/fixed/fixed_sqrt_ui32.c
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+/* fixed_sqrt_ui32.c */
+/* avr.math.fixed - Fixed point math module. {{{
+ *
+ * Copyright (C) 2005 Nicolas Schodet
+ *
+ * Robot APB Team/Efrei 2006.
+ * Web: http://assos.efrei.fr/robot/
+ * Email: robot AT efrei DOT fr
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * }}} */
+#include "common.h"
+#include "fixed.h"
+
+/** Compute square root, ui32 -> ui16. */
+uint16_t
+fixed_sqrt_ui32 (uint32_t x)
+{
+ uint32_t root, bit, test;
+ root = 0;
+ bit = 1L << 30;
+ do
+ {
+ test = root + bit;
+ if (x >= test)
+ {
+ x -= test;
+ root = test + bit;
+ }
+ root >>= 1;
+ bit >>= 2;
+ } while (bit);
+ return root;
+}
+