rockbox/lib/fixedpoint/fixedpoint.h
Michael Sevakis aced667f48 Undo hacks to meant to get around string formatting limitations
The new vuprintf makes unnecessary workarounds due to formatting
limitations. I checked grep output for whatever appeared to fit
but it's possible I missed some instances because they weren't
so obvious.

Also, this means sound settings can dynamically work with any
number of decimals rather than the current assumption of one or
two. Add an ipow() function to help and take advantage of dynamic
field width and precision. Consolidate string formatting of sound
settings.

Change-Id: I46caf534859dfd1916cd440cd25e5206b192fcd8
2017-11-21 05:01:14 -05:00

122 lines
4.4 KiB
C

/***************************************************************************
* __________ __ ___.
* 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)
*
* 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);
long ipow(long x, long y);
/* 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 */