apps/fixedpoint.h

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id: fixedpoint.h -1   $
   9  *
  10  * Copyright (C) 2006 Jens Arnold
  11  *
  12  * Fixed point library for plugins
  13  *
  14  * This program is free software; you can redistribute it and/or
  15  * modify it under the terms of the GNU General Public License
  16  * as published by the Free Software Foundation; either version 2
  17  * of the License, or (at your option) any later version.
  18  *
  19  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  20  * KIND, either express or implied.
  21  *
  22  ****************************************************************************/
  23
  24 /** FIXED POINT MATH ROUTINES - USAGE
  25  *
  26  *  - x and y arguments are fixed point integers
  27  *  - fracbits is the number of fractional bits in the argument(s)
  28  *  - functions return long fixed point integers with the specified number
  29  *    of fractional bits unless otherwise specified
  30  *
  31  *  Multiply two fixed point numbers:
  32  *      fp_mul(x, y, fracbits)
  33  *
  34  *  Shortcut: Multiply two fixed point numbers with 31 fractional bits:
  35  *      fp31_mul(x, y)
  36  *
  37  *  Shortcut: Multiply two fixed point numbers with 31 fractional bits,
  38  *          then shift left by z bits:
  39  *      fp31_mulshl(x, y, z)
  40  *          NOTE: z must be in the range 1-8 on Coldfire targets.
  41  *
  42  *  Divide two fixed point numbers:
  43  *      fp_div(x, y, fracbits)
  44  *
  45  *  Take square root of a fixed point number:
  46  *      fp_sqrt(x, fracbits)
  47  *
  48  *  Calculate sin and cos of an angle:
  49  *      fp_sincos(phase, *cos)
  50  *          where phase is a 32 bit unsigned integer with 0 representing 0
  51  *          and 0xFFFFFFFF representing 2*pi, and *cos is the address to
  52  *          a long signed integer.  Value returned is a long signed integer
  53  *          from LONG_MIN to LONG_MAX, representing -1 to 1 respectively.
  54  *          That is, value is a fixed point integer with 31 fractional bits.
  55  *
  56  *  Calculate sin or cos of an angle (very fast, from a table):
  57  *      fp14_sin(angle)
  58  *      fp14_cos(angle)
  59  *          where angle is a non-fixed point integer in degrees.  Value
  60  *          returned is a fixed point integer with 14 fractional bits.
  61  *
  62  *  Calculate decibel equivalent of a gain factor:
  63  *      fp_decibels(factor, fracbits)
  64  *          where fracbits is in the range 12 to 22 (higher is better),
  65  *          and factor is a positive fixed point integer.
  66  *
  67  *  Calculate factor equivalent of a decibel value:
  68  *      fp_factor(decibels, fracbits)
  69  *          where fracbits is in the range 12 to 22 (lower is better),
  70  *          and decibels is a fixed point integer.
  71  */
  72
  73 #ifndef _FIXEDPOINT_H
  74 #define _FIXEDPOINT_H
  75
  76 #include <inttypes.h>
  77
  78 /* Redefine function names, making sure legacy code is usable */
  79 #define fp31_mul(x, y)          FRACMUL(x, y)
  80 #define fp31_mulshl(x, y, z)    FRACMUL_SHL(x, y, z)
  81 #define fp_div(x, y, z)         DIV64(x, y, z)
  82 #define fp_sqrt(x, y)           fsqrt(x, y)
  83 #define fp_sincos(x, y)         fsincos(x, y)
  84 #define fp14_sin(x)             sin_int(x)
  85 #define fp14_cos(x)             cos_int(x)
  86 #define fp16_log(x)             flog(x)
  87
  88
  89 #define fp_mul(x, y, z) (long)((((long long)(x)) * ((long long)(y))) >> (z))
  90 #define DIV64(x, y, z) (long)((((long long)(x)) << (z)) / ((long long)(y)))
  91
  92 /** TAKEN FROM apps/dsp.h */
  93 /* A bunch of fixed point assembler helper macros */
  94 #if defined(CPU_COLDFIRE)
  95 /* These macros use the Coldfire EMAC extension and need the MACSR flags set
  96  * to fractional mode with no rounding.
  97  */
  98
  99 /* Multiply two S.31 fractional integers and return the sign bit and the
 100  * 31 most significant bits of the result.
 101  */
 102 #define FRACMUL(x, y) \
 103 ({ \
 104     long t; \
 105     asm ("mac.l    %[a], %[b], %%acc0\n\t" \
 106          "movclr.l %%acc0, %[t]\n\t" \
 107          : [t] "=r" (t) : [a] "r" (x), [b] "r" (y)); \
 108     t; \
 109 })
 110
 111 /* Multiply two S.31 fractional integers, and return the 32 most significant
 112  * bits after a shift left by the constant z. NOTE: Only works for shifts of
 113  * 1 to 8 on Coldfire!
 114  */
 115 #define FRACMUL_SHL(x, y, z) \
 116 ({ \
 117     long t, t2; \
 118     asm ("mac.l    %[a], %[b], %%acc0\n\t" \
 119          "moveq.l  %[d], %[t]\n\t" \
 120          "move.l   %%accext01, %[t2]\n\t" \
 121          "and.l    %[mask], %[t2]\n\t" \
 122          "lsr.l    %[t], %[t2]\n\t" \
 123          "movclr.l %%acc0, %[t]\n\t" \
 124          "asl.l    %[c], %[t]\n\t" \
 125          "or.l     %[t2], %[t]\n\t" \
 126          : [t] "=&d" (t), [t2] "=&d" (t2) \
 127          : [a] "r" (x), [b] "r" (y), [mask] "d" (0xff), \
 128            [c] "i" ((z)), [d] "i" (8 - (z))); \
 129     t; \
 130 })
 131
 132 #elif defined(CPU_ARM)
 133
 134 /* Multiply two S.31 fractional integers and return the sign bit and the
 135  * 31 most significant bits of the result.
 136  */
 137 #define FRACMUL(x, y) \
 138 ({ \
 139     long t, t2; \
 140     asm ("smull    %[t], %[t2], %[a], %[b]\n\t" \
 141          "mov      %[t2], %[t2], asl #1\n\t" \
 142          "orr      %[t], %[t2], %[t], lsr #31\n\t" \
 143          : [t] "=&r" (t), [t2] "=&r" (t2) \
 144          : [a] "r" (x), [b] "r" (y)); \
 145     t; \
 146 })
 147
 148 /* Multiply two S.31 fractional integers, and return the 32 most significant
 149  * bits after a shift left by the constant z.
 150  */
 151 #define FRACMUL_SHL(x, y, z) \
 152 ({ \
 153     long t, t2; \
 154     asm ("smull    %[t], %[t2], %[a], %[b]\n\t" \
 155          "mov      %[t2], %[t2], asl %[c]\n\t" \
 156          "orr      %[t], %[t2], %[t], lsr %[d]\n\t" \
 157          : [t] "=&r" (t), [t2] "=&r" (t2) \
 158          : [a] "r" (x), [b] "r" (y), \
 159            [c] "M" ((z) + 1), [d] "M" (31 - (z))); \
 160     t; \
 161 })
 162
 163 #else
 164
 165 #define FRACMUL(x, y) (long) (((((long long) (x)) * ((long long) (y))) >> 31))
 166 #define FRACMUL_SHL(x, y, z) \
 167 ((long)(((((long long) (x)) * ((long long) (y))) >> (31 - (z)))))
 168
 169 #endif
 170
 171 /** TAKEN FROM ORIGINAL fixedpoint.h */
 172 /* fast unsigned multiplication (16x16bit->32bit or 32x32bit->32bit,
 173  * whichever is faster for the architecture) */
 174 #ifdef CPU_ARM
 175 #define FMULU(a, b) ((uint32_t) (((uint32_t) (a)) * ((uint32_t) (b))))
 176 #else /* SH1, coldfire */
 177 #define FMULU(a, b) ((uint32_t) (((uint16_t) (a)) * ((uint16_t) (b))))
 178 #endif
 179
 180 long fsincos(unsigned long phase, long *cos);
 181 long fsqrt(long x, unsigned int fracbits);
 182 long sin_int(int val);
 183 long cos_int(int val);
 184 long flog(int x);
 185
 186
 187 /** MODIFIED FROM replaygain.c */
 188 #define FP_INF          (0x7fffffff)
 189 #define FP_NEGINF      -(0x7fffffff)
 190
 191 /* fracbits in range 12 - 22 work well. Higher is better for
 192  * calculating dB, lower is better for calculating ratio.
 193  */
 194 long fp_decibels(unsigned long factor, unsigned int fracbits);
 195 long fp_factor(long decibels, unsigned int fracbits);
 196
 197 #endif