1 files changed, 87 insertions, 0 deletions
diff --git a/include/linux/fixp-arith.h b/include/linux/fixp-arith.h
new file mode 100644
index 000000000000..3089d7382325
--- /dev/null
+++ b/include/linux/fixp-arith.h
@@ -0,0 +1,87 @@
+#ifndef _FIXP_ARITH_H
+#define _FIXP_ARITH_H
+
+/*
+ * Simplistic fixed-point arithmetics.
+ * Hmm, I'm probably duplicating some code :(
+ *
+ * Copyright (c) 2002 Johann Deneux
+ */
+
+/*
+ * 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
+ *
+ * Should you need to contact me, the author, you can do so by
+ * e-mail - mail your message to <johann.deneux@gmail.com>
+ */
+
+#include <linux/types.h>
+
+/* The type representing fixed-point values */
+typedef s16 fixp_t;
+
+#define FRAC_N 8
+#define FRAC_MASK ((1<<FRAC_N)-1)
+
+/* Not to be used directly. Use fixp_{cos,sin} */
+static const fixp_t cos_table[46] = {
+	0x0100,	0x00FF,	0x00FF,	0x00FE,	0x00FD,	0x00FC,	0x00FA,	0x00F8,
+	0x00F6,	0x00F3,	0x00F0,	0x00ED,	0x00E9,	0x00E6,	0x00E2,	0x00DD,
+	0x00D9,	0x00D4,	0x00CF,	0x00C9,	0x00C4,	0x00BE,	0x00B8,	0x00B1,
+	0x00AB,	0x00A4,	0x009D,	0x0096,	0x008F,	0x0087,	0x0080,	0x0078,
+	0x0070,	0x0068,	0x005F,	0x0057,	0x004F,	0x0046,	0x003D,	0x0035,
+	0x002C,	0x0023,	0x001A,	0x0011,	0x0008, 0x0000
+};
+
+
+/* a: 123 -> 123.0 */
+static inline fixp_t fixp_new(s16 a)
+{
+	return a<<FRAC_N;
+}
+
+/* a: 0xFFFF -> -1.0
+      0x8000 -> 1.0
+      0x0000 -> 0.0
+*/
+static inline fixp_t fixp_new16(s16 a)
+{
+	return ((s32)a)>>(16-FRAC_N);
+}
+
+static inline fixp_t fixp_cos(unsigned int degrees)
+{
+	int quadrant = (degrees / 90) & 3;
+	unsigned int i = degrees % 90;
+
+	if (quadrant == 1 || quadrant == 3)
+		i = 90 - i;
+
+	i >>= 1;
+
+	return (quadrant == 1 || quadrant == 2)? -cos_table[i] : cos_table[i];
+}
+
+static inline fixp_t fixp_sin(unsigned int degrees)
+{
+	return -fixp_cos(degrees + 90);
+}
+
+static inline fixp_t fixp_mult(fixp_t a, fixp_t b)
+{
+	return ((s32)(a*b))>>FRAC_N;
+}
+
+#endif