Take 2 at 'Consolidate all fixed point math routines in one library' (FS#10400) by Jeffrey Goode

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@21664 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 49 insertions, 0 deletions

diff --git a/apps/codecs/lib/fixedpoint.h b/apps/codecs/lib/fixedpoint.h
new file mode 100644
index 0000000000..e6ed5208ca
--- /dev/null
+++ b/apps/codecs/lib/fixedpoint.h
@@ -0,0 +1,49 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id: fixedpoint.h -1   $
+ *
+ * Copyright (C) 2006 Jens Arnold
+ *
+ * Fixed point library for plugins
+ *
+ * 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 software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+ /** CODECS - FIXED POINT MATH ROUTINES - USAGE
+ *
+ *  - x and y arguments are fixed point integers
+ *  - fracbits is the number of fractional bits in the argument(s)
+ *  - functions return long fixed point integers with the specified number
+ *    of fractional bits unless otherwise specified
+ *
+ *  Calculate sin and cos of an angle:
+ *      fp_sincos(phase, *cos)
+ *          where phase is a 32 bit unsigned integer with 0 representing 0
+ *          and 0xFFFFFFFF representing 2*pi, and *cos is the address to
+ *          a long signed integer.  Value returned is a long signed integer
+ *          from LONG_MIN to LONG_MAX, representing -1 to 1 respectively.
+ *          That is, value is a fixed point integer with 31 fractional bits.
+ *
+ *  Take square root of a fixed point number:
+ *      fp_sqrt(x, fracbits)
+ *
+ */
+#ifndef _FIXEDPOINT_H_CODECS
+#define _FIXEDPOINT_H_CODECS
+
+long fp_sincos(unsigned long phase, long *cos);
+long fp_sqrt(long a, unsigned int fracbits);
+
+#endif