30e2f42c82
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@26470 a1c6a512-1295-4272-9138-f99709370657
74 lines
2.8 KiB
C
74 lines
2.8 KiB
C
/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Copyright (C) 2006 Jens Arnold
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*
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* Fixed point library for plugins
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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/** PLUGINS - FIXED POINT MATH ROUTINES - USAGE
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*
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* - x and y arguments are fixed point integers
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* - fracbits is the number of fractional bits in the argument(s)
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* - functions return long fixed point integers with the specified number
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* of fractional bits unless otherwise specified
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*
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* Calculate sin and cos of an angle:
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* fp_sincos(phase, *cos)
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* where phase is a 32 bit unsigned integer with 0 representing 0
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* and 0xFFFFFFFF representing 2*pi, and *cos is the address to
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* a long signed integer. Value returned is a long signed integer
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* from LONG_MIN to LONG_MAX, representing -1 to 1 respectively.
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* That is, value is a fixed point integer with 31 fractional bits.
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*
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* Take square root of a fixed point number:
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* fp_sqrt(x, fracbits)
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*
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* Calculate sin or cos of an angle (very fast, from a table):
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* fp14_sin(angle)
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* fp14_cos(angle)
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* where angle is a non-fixed point integer in degrees. Value
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* returned is a fixed point integer with 14 fractional bits.
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*
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* Calculate the natural log of a positive fixed point integer
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* fp16_log(x)
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* where x and the value returned are fixed point integers
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* with 16 fractional bits.
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*/
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#ifndef _FIXEDPOINT_H_PLUGINS
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#define _FIXEDPOINT_H_PLUGINS
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long fp_sincos(unsigned long phase, long *cos);
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long fp_sqrt(long a, unsigned int fracbits);
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long fp14_cos(int val);
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long fp14_sin(int val);
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long fp16_log(int x);
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long fp16_exp(int x);
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unsigned long isqrt(unsigned long x);
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/* fast unsigned multiplication (16x16bit->32bit or 32x32bit->32bit,
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* whichever is faster for the architecture) */
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#ifdef CPU_ARM
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#define FMULU(a, b) ((uint32_t) (((uint32_t) (a)) * ((uint32_t) (b))))
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#else /* SH1, coldfire */
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#define FMULU(a, b) ((uint32_t) (((uint16_t) (a)) * ((uint16_t) (b))))
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#endif
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#endif
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