apps/codecs/libatrac/fixp_math.h

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2009 Mohamed Tarek
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  18  * KIND, either express or implied.
  19  *
  20  ****************************************************************************/
  21 #include <stdlib.h>
  22 #include <inttypes.h>
  23
  24 /* Macros for converting between various fixed-point representations and floating point. */
  25 #define ONE_16 (1L << 16)
  26 #define fixtof64(x)       (float)((float)(x) / (float)(1 << 16))        //does not work on int64_t!
  27 #define ftofix32(x)       ((int32_t)((x) * (float)(1 << 16) + ((x) < 0 ? -0.5 : 0.5)))
  28 #define ftofix31(x)       ((int32_t)((x) * (float)(1 << 31) + ((x) < 0 ? -0.5 : 0.5)))
  29 #define fix31tof64(x)     (float)((float)(x) / (float)(1 << 31))
  30
  31 /* Fixed point math routines for use in atrac3.c */
  32
  33 #if defined(CPU_ARM)
  34     #define fixmul16(X,Y) \
  35      ({ \
  36         int32_t low; \
  37         int32_t high; \
  38         asm volatile (                   /* calculates: result = (X*Y)>>16 */ \
  39            "smull  %0,%1,%2,%3 \n\t"     /* 64 = 32x32 multiply */ \
  40            "mov %0, %0, lsr #16 \n\t"    /* %0 = %0 >> 16 */ \
  41            "orr %0, %0, %1, lsl #16 \n\t"/* result = %0 OR (%1 << 16) */ \
  42            : "=&r"(low), "=&r" (high) \
  43            : "r"(X),"r"(Y)); \
  44         low; \
  45      })
  46
  47     #define fixmul31(X,Y) \
  48      ({ \
  49         int32_t low; \
  50         int32_t high; \
  51         asm volatile (                   /* calculates: result = (X*Y)>>31 */ \
  52            "smull  %0,%1,%2,%3 \n\t"     /* 64 = 32x32 multiply */ \
  53            "mov %0, %0, lsr #31 \n\t"    /* %0 = %0 >> 31 */ \
  54            "orr %0, %0, %1, lsl #1 \n\t" /* result = %0 OR (%1 << 1) */ \
  55            : "=&r"(low), "=&r" (high) \
  56            : "r"(X),"r"(Y)); \
  57         low; \
  58      })
  59 #elif defined(CPU_COLDFIRE)
  60     #define fixmul16(X,Y) \
  61     ({ \
  62         int32_t t1, t2; \
  63         asm volatile ( \
  64             "mac.l   %[x],%[y],%%acc0\n\t" /* multiply */ \
  65             "mulu.l  %[y],%[x]   \n\t"     /* get lower half, avoid emac stall */ \
  66             "movclr.l %%acc0,%[t1]   \n\t" /* get higher half */ \
  67             "moveq.l #15,%[t2]   \n\t" \
  68             "asl.l   %[t2],%[t1] \n\t"     /* hi <<= 15, plus one free */ \
  69             "moveq.l #16,%[t2]   \n\t" \
  70             "lsr.l   %[t2],%[x]  \n\t"     /* (unsigned)lo >>= 16 */ \
  71             "or.l    %[x],%[t1]  \n\t"     /* combine result */ \
  72             : /* outputs */ \
  73             [t1]"=&d"(t1), \
  74             [t2]"=&d"(t2) \
  75             : /* inputs */ \
  76             [x] "d" ((X)), \
  77             [y] "d" ((Y))); \
  78         t1; \
  79     })
  80
  81     #define fixmul31(X,Y) \
  82     ({ \
  83        int32_t t; \
  84        asm volatile ( \
  85           "mac.l %[x], %[y], %%acc0\n\t"   /* multiply */ \
  86           "movclr.l %%acc0, %[t]\n\t"      /* get higher half as result */ \
  87           : [t] "=d" (t) \
  88           : [x] "r" ((X)), [y] "r" ((Y))); \
  89        t; \
  90     })
  91 #else
  92     static inline int32_t fixmul16(int32_t x, int32_t y)
  93     {
  94         int64_t temp;
  95         temp = x;
  96         temp *= y;
  97
  98         temp >>= 16;
  99
 100         return (int32_t)temp;
 101     }
 102
 103     static inline int32_t fixmul31(int32_t x, int32_t y)
 104     {
 105         int64_t temp;
 106         temp = x;
 107         temp *= y;
 108
 109         temp >>= 31;        //16+31-16 = 31 bits
 110
 111         return (int32_t)temp;
 112     }
 113 #endif