libavcodec/mathops.h

   1 /*
   2  * simple math operations
   3  * Copyright (c) 2001, 2002 Fabrice Bellard
   4  * Copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at> et al
   5  *
   6  * This file is part of Libav.
   7  *
   8  * Libav is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * Libav is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with Libav; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22 #ifndef AVCODEC_MATHOPS_H
  23 #define AVCODEC_MATHOPS_H
  24
  25 #include <stdint.h>
  26
  27 #include "libavutil/common.h"
  28 #include "config.h"
  29
  30 extern const uint32_t ff_inverse[257];
  31 extern const uint8_t  ff_reverse[256];
  32 extern const uint8_t ff_sqrt_tab[256];
  33
  34 #if   ARCH_ARM
  35 #   include "arm/mathops.h"
  36 #elif ARCH_AVR32
  37 #   include "avr32/mathops.h"
  38 #elif ARCH_BFIN
  39 #   include "bfin/mathops.h"
  40 #elif ARCH_MIPS
  41 #   include "mips/mathops.h"
  42 #elif ARCH_PPC
  43 #   include "ppc/mathops.h"
  44 #elif ARCH_X86
  45 #   include "x86/mathops.h"
  46 #endif
  47
  48 /* generic implementation */
  49
  50 #ifndef MUL64
  51 #   define MUL64(a,b) ((int64_t)(a) * (int64_t)(b))
  52 #endif
  53
  54 #ifndef MULL
  55 #   define MULL(a,b,s) (MUL64(a, b) >> (s))
  56 #endif
  57
  58 #ifndef MULH
  59 static av_always_inline int MULH(int a, int b){
  60     return MUL64(a, b) >> 32;
  61 }
  62 #endif
  63
  64 #ifndef UMULH
  65 static av_always_inline unsigned UMULH(unsigned a, unsigned b){
  66     return ((uint64_t)(a) * (uint64_t)(b))>>32;
  67 }
  68 #endif
  69
  70 #ifndef MAC64
  71 #   define MAC64(d, a, b) ((d) += MUL64(a, b))
  72 #endif
  73
  74 #ifndef MLS64
  75 #   define MLS64(d, a, b) ((d) -= MUL64(a, b))
  76 #endif
  77
  78 /* signed 16x16 -> 32 multiply add accumulate */
  79 #ifndef MAC16
  80 #   define MAC16(rt, ra, rb) rt += (ra) * (rb)
  81 #endif
  82
  83 /* signed 16x16 -> 32 multiply */
  84 #ifndef MUL16
  85 #   define MUL16(ra, rb) ((ra) * (rb))
  86 #endif
  87
  88 #ifndef MLS16
  89 #   define MLS16(rt, ra, rb) ((rt) -= (ra) * (rb))
  90 #endif
  91
  92 /* median of 3 */
  93 #ifndef mid_pred
  94 #define mid_pred mid_pred
  95 static inline av_const int mid_pred(int a, int b, int c)
  96 {
  97 #if 0
  98     int t= (a-b)&((a-b)>>31);
  99     a-=t;
 100     b+=t;
 101     b-= (b-c)&((b-c)>>31);
 102     b+= (a-b)&((a-b)>>31);
 103
 104     return b;
 105 #else
 106     if(a>b){
 107         if(c>b){
 108             if(c>a) b=a;
 109             else    b=c;
 110         }
 111     }else{
 112         if(b>c){
 113             if(c>a) b=c;
 114             else    b=a;
 115         }
 116     }
 117     return b;
 118 #endif
 119 }
 120 #endif
 121
 122 #ifndef sign_extend
 123 static inline av_const int sign_extend(int val, unsigned bits)
 124 {
 125     unsigned shift = 8 * sizeof(int) - bits;
 126     union { unsigned u; int s; } v = { (unsigned) val << shift };
 127     return v.s >> shift;
 128 }
 129 #endif
 130
 131 #ifndef zero_extend
 132 static inline av_const unsigned zero_extend(unsigned val, unsigned bits)
 133 {
 134     return (val << ((8 * sizeof(int)) - bits)) >> ((8 * sizeof(int)) - bits);
 135 }
 136 #endif
 137
 138 #ifndef COPY3_IF_LT
 139 #define COPY3_IF_LT(x, y, a, b, c, d)\
 140 if ((y) < (x)) {\
 141     (x) = (y);\
 142     (a) = (b);\
 143     (c) = (d);\
 144 }
 145 #endif
 146
 147 #ifndef MASK_ABS
 148 #define MASK_ABS(mask, level) do {              \
 149         mask  = level >> 31;                    \
 150         level = (level ^ mask) - mask;          \
 151     } while (0)
 152 #endif
 153
 154 #ifndef NEG_SSR32
 155 #   define NEG_SSR32(a,s) ((( int32_t)(a))>>(32-(s)))
 156 #endif
 157
 158 #ifndef NEG_USR32
 159 #   define NEG_USR32(a,s) (((uint32_t)(a))>>(32-(s)))
 160 #endif
 161
 162 #if HAVE_BIGENDIAN
 163 # ifndef PACK_2U8
 164 #   define PACK_2U8(a,b)     (((a) <<  8) | (b))
 165 # endif
 166 # ifndef PACK_4U8
 167 #   define PACK_4U8(a,b,c,d) (((a) << 24) | ((b) << 16) | ((c) << 8) | (d))
 168 # endif
 169 # ifndef PACK_2U16
 170 #   define PACK_2U16(a,b)    (((a) << 16) | (b))
 171 # endif
 172 #else
 173 # ifndef PACK_2U8
 174 #   define PACK_2U8(a,b)     (((b) <<  8) | (a))
 175 # endif
 176 # ifndef PACK_4U2
 177 #   define PACK_4U8(a,b,c,d) (((d) << 24) | ((c) << 16) | ((b) << 8) | (a))
 178 # endif
 179 # ifndef PACK_2U16
 180 #   define PACK_2U16(a,b)    (((b) << 16) | (a))
 181 # endif
 182 #endif
 183
 184 #ifndef PACK_2S8
 185 #   define PACK_2S8(a,b)     PACK_2U8((a)&255, (b)&255)
 186 #endif
 187 #ifndef PACK_4S8
 188 #   define PACK_4S8(a,b,c,d) PACK_4U8((a)&255, (b)&255, (c)&255, (d)&255)
 189 #endif
 190 #ifndef PACK_2S16
 191 #   define PACK_2S16(a,b)    PACK_2U16((a)&0xffff, (b)&0xffff)
 192 #endif
 193
 194 #ifndef FASTDIV
 195 #   define FASTDIV(a,b) ((uint32_t)((((uint64_t)a) * ff_inverse[b]) >> 32))
 196 #endif /* FASTDIV */
 197
 198 static inline av_const unsigned int ff_sqrt(unsigned int a)
 199 {
 200     unsigned int b;
 201
 202     if (a < 255) return (ff_sqrt_tab[a + 1] - 1) >> 4;
 203     else if (a < (1 << 12)) b = ff_sqrt_tab[a >> 4] >> 2;
 204 #if !CONFIG_SMALL
 205     else if (a < (1 << 14)) b = ff_sqrt_tab[a >> 6] >> 1;
 206     else if (a < (1 << 16)) b = ff_sqrt_tab[a >> 8]   ;
 207 #endif
 208     else {
 209         int s = av_log2_16bit(a >> 16) >> 1;
 210         unsigned int c = a >> (s + 2);
 211         b = ff_sqrt_tab[c >> (s + 8)];
 212         b = FASTDIV(c,b) + (b << s);
 213     }
 214
 215     return b - (a < b * b);
 216 }
 217
 218 #endif /* AVCODEC_MATHOPS_H */