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Diffstat (limited to 'firmware/include/fixedpoint.h')
| -rw-r--r-- | firmware/include/fixedpoint.h | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/firmware/include/fixedpoint.h b/firmware/include/fixedpoint.h new file mode 100644 index 0000000000..3e14bdd68e --- /dev/null +++ b/firmware/include/fixedpoint.h @@ -0,0 +1,111 @@ +/*************************************************************************** + * __________ __ ___. + * 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) + +/* fracbits in range 12 - 22 work well. Higher is better for + * calculating dB, lower is better for calculating factor. + */ +/* long fp_decibels(unsigned long factor, unsigned int fracbits); */ +long fp_factor(long decibels, unsigned int fracbits); + +#endif /* FIXEDPOINT_H */ |