Make fixepoint.c as a shared library (libfixedpoint.a).

Change-Id: Icc10d6e85f890c432f191233a4d64e09f00be43d Reviewed-on: http://gerrit.rockbox.org/456 Reviewed-by: Michael Sevakis <jethead71@rockbox.org> Tested-by: Michael Sevakis <jethead71@rockbox.org>
2013-04-16 17:47:58 -04:00 · 2013-04-16 17:47:58 -04:00 · 95e23defb0
commit 95e23defb0
parent 8829e909b4
28 changed files with 91 additions and 101 deletions
--- a/lib/fixedpoint/fixedpoint.h
+++ b/lib/fixedpoint/fixedpoint.h
@ -0,0 +1,125 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * 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.
+ *
+ ****************************************************************************/
+
+/** 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
+ *
+ *  Multiply two fixed point numbers:
+ *      fp_mul(x, y, fracbits)
+ *
+ *  Divide two fixed point numbers:
+ *      fp_div(x, y, fracbits)
+ *
+ *  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 -0x80000000 to 0x7fffffff, 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)
+ *
+ *  Take the square root of an integer:
+ *      isqrt(x)
+ *
+ *  Calculate sin or cos of an angle (very fast, from a table):
+ *      fp14_sin(angle)
+ *      fp14_cos(angle)
+ *          where angle is a non-fixed point integer in degrees.  Value
+ *          returned is a fixed point integer with 14 fractional bits.
+ *
+ *  Calculate the exponential of a fixed point integer
+ *      fp16_exp(x)
+ *          where x and the value returned are fixed point integers
+ *          with 16 fractional bits.
+ *
+ *  Calculate the natural log of a positive fixed point integer
+ *      fp16_log(x)
+ *          where x and the value returned are fixed point integers
+ *          with 16 fractional bits.
+ *
+ *  Calculate decibel equivalent of a gain factor:
+ *      fp_decibels(factor, fracbits)
+ *          where fracbits is in the range 12 to 22 (higher is better),
+ *          and factor is a positive fixed point integer.
+ *
+ *  Calculate factor equivalent of a decibel value:
+ *      fp_factor(decibels, fracbits)
+ *          where fracbits is in the range 12 to 22 (lower is better),
+ *          and decibels is a fixed point integer.
+ */
+
+#ifndef FIXEDPOINT_H
+#define FIXEDPOINT_H
+
+#define fp_mul(x, y, z) (long)((((long long)(x)) * ((long long)(y))) >> (z))
+#define fp_div(x, y, z) (long)((((long long)(x)) << (z)) / ((long long)(y)))
+
+long fp_sincos(unsigned long phase, long *cos);
+long fp_sqrt(long a, unsigned int fracbits);
+long fp14_cos(int val);
+long fp14_sin(int val);
+long fp16_log(int x);
+long fp16_exp(int x);
+
+unsigned long isqrt(unsigned long x);
+
+/* fast unsigned multiplication (16x16bit->32bit or 32x32bit->32bit,
+ * whichever is faster for the architecture) */
+#ifdef CPU_ARM
+#define FMULU(a, b) ((uint32_t) (((uint32_t) (a)) * ((uint32_t) (b))))
+#else /* SH1, coldfire */
+#define FMULU(a, b) ((uint32_t) (((uint16_t) (a)) * ((uint16_t) (b))))
+#endif
+
+/** MODIFIED FROM replaygain.c */
+#define FP_INF          (0x7fffffff)
+#define FP_NEGINF      -(0x7fffffff)
+
+/** FIXED POINT EXP10
+ * Return 10^x as FP integer.  Argument is FP integer.
+ */
+long fp_exp10(long x, unsigned int fracbits);
+
+/** FIXED POINT LOG10
+ * Return log10(x) as FP integer.  Argument is FP integer.
+ */
+long fp_log10(long n, unsigned int fracbits);
+
+/* fracbits in range 12 - 22 work well. Higher is better for
+ * calculating dB, lower is better for calculating factor.
+ */
+
+/** CONVERT FACTOR TO DECIBELS */
+long fp_decibels(unsigned long factor, unsigned int fracbits);
+
+/** CONVERT DECIBELS TO FACTOR */
+long fp_factor(long decibels, unsigned int fracbits);
+
+#endif /* FIXEDPOINT_H */