FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
mathops.h
Go to the documentation of this file.
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 FFmpeg.
7  *
8  * FFmpeg 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  * FFmpeg 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 FFmpeg; 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 #define MAX_NEG_CROP 1024
31 
32 extern const uint32_t ff_inverse[257];
33 extern const uint8_t ff_reverse[256];
34 extern const uint8_t ff_sqrt_tab[256];
35 extern const uint8_t ff_crop_tab[256 + 2 * MAX_NEG_CROP];
36 extern const uint8_t ff_zigzag_direct[64];
37 
38 #if ARCH_ARM
39 # include "arm/mathops.h"
40 #elif ARCH_AVR32
41 # include "avr32/mathops.h"
42 #elif ARCH_MIPS
43 # include "mips/mathops.h"
44 #elif ARCH_PPC
45 # include "ppc/mathops.h"
46 #elif ARCH_X86
47 # include "x86/mathops.h"
48 #endif
49 
50 /* generic implementation */
51 
52 #ifndef MUL64
53 # define MUL64(a,b) ((int64_t)(a) * (int64_t)(b))
54 #endif
55 
56 #ifndef MULL
57 # define MULL(a,b,s) (MUL64(a, b) >> (s))
58 #endif
59 
60 #ifndef MULH
61 static av_always_inline int MULH(int a, int b){
62  return MUL64(a, b) >> 32;
63 }
64 #endif
65 
66 #ifndef UMULH
67 static av_always_inline unsigned UMULH(unsigned a, unsigned b){
68  return ((uint64_t)(a) * (uint64_t)(b))>>32;
69 }
70 #endif
71 
72 #ifndef MAC64
73 # define MAC64(d, a, b) ((d) += MUL64(a, b))
74 #endif
75 
76 #ifndef MLS64
77 # define MLS64(d, a, b) ((d) -= MUL64(a, b))
78 #endif
79 
80 /* signed 16x16 -> 32 multiply add accumulate */
81 #ifndef MAC16
82 # define MAC16(rt, ra, rb) rt += (ra) * (rb)
83 #endif
84 
85 /* signed 16x16 -> 32 multiply */
86 #ifndef MUL16
87 # define MUL16(ra, rb) ((ra) * (rb))
88 #endif
89 
90 #ifndef MLS16
91 # define MLS16(rt, ra, rb) ((rt) -= (ra) * (rb))
92 #endif
93 
94 /* median of 3 */
95 #ifndef mid_pred
96 #define mid_pred mid_pred
97 static inline av_const int mid_pred(int a, int b, int c)
98 {
99 #if 0
100  int t= (a-b)&((a-b)>>31);
101  a-=t;
102  b+=t;
103  b-= (b-c)&((b-c)>>31);
104  b+= (a-b)&((a-b)>>31);
105 
106  return b;
107 #else
108  if(a>b){
109  if(c>b){
110  if(c>a) b=a;
111  else b=c;
112  }
113  }else{
114  if(b>c){
115  if(c>a) b=c;
116  else b=a;
117  }
118  }
119  return b;
120 #endif
121 }
122 #endif
123 
124 #ifndef sign_extend
125 static inline av_const int sign_extend(int val, unsigned bits)
126 {
127  unsigned shift = 8 * sizeof(int) - bits;
128  union { unsigned u; int s; } v = { (unsigned) val << shift };
129  return v.s >> shift;
130 }
131 #endif
132 
133 #ifndef zero_extend
134 static inline av_const unsigned zero_extend(unsigned val, unsigned bits)
135 {
136  return (val << ((8 * sizeof(int)) - bits)) >> ((8 * sizeof(int)) - bits);
137 }
138 #endif
139 
140 #ifndef COPY3_IF_LT
141 #define COPY3_IF_LT(x, y, a, b, c, d)\
142 if ((y) < (x)) {\
143  (x) = (y);\
144  (a) = (b);\
145  (c) = (d);\
146 }
147 #endif
148 
149 #ifndef MASK_ABS
150 #define MASK_ABS(mask, level) do { \
151  mask = level >> 31; \
152  level = (level ^ mask) - mask; \
153  } while (0)
154 #endif
155 
156 #ifndef NEG_SSR32
157 # define NEG_SSR32(a,s) ((( int32_t)(a))>>(32-(s)))
158 #endif
159 
160 #ifndef NEG_USR32
161 # define NEG_USR32(a,s) (((uint32_t)(a))>>(32-(s)))
162 #endif
163 
164 #if HAVE_BIGENDIAN
165 # ifndef PACK_2U8
166 # define PACK_2U8(a,b) (((a) << 8) | (b))
167 # endif
168 # ifndef PACK_4U8
169 # define PACK_4U8(a,b,c,d) (((a) << 24) | ((b) << 16) | ((c) << 8) | (d))
170 # endif
171 # ifndef PACK_2U16
172 # define PACK_2U16(a,b) (((a) << 16) | (b))
173 # endif
174 #else
175 # ifndef PACK_2U8
176 # define PACK_2U8(a,b) (((b) << 8) | (a))
177 # endif
178 # ifndef PACK_4U2
179 # define PACK_4U8(a,b,c,d) (((d) << 24) | ((c) << 16) | ((b) << 8) | (a))
180 # endif
181 # ifndef PACK_2U16
182 # define PACK_2U16(a,b) (((b) << 16) | (a))
183 # endif
184 #endif
185 
186 #ifndef PACK_2S8
187 # define PACK_2S8(a,b) PACK_2U8((a)&255, (b)&255)
188 #endif
189 #ifndef PACK_4S8
190 # define PACK_4S8(a,b,c,d) PACK_4U8((a)&255, (b)&255, (c)&255, (d)&255)
191 #endif
192 #ifndef PACK_2S16
193 # define PACK_2S16(a,b) PACK_2U16((a)&0xffff, (b)&0xffff)
194 #endif
195 
196 #ifndef FASTDIV
197 # define FASTDIV(a,b) ((uint32_t)((((uint64_t)a) * ff_inverse[b]) >> 32))
198 #endif /* FASTDIV */
199 
200 static inline av_const unsigned int ff_sqrt(unsigned int a)
201 {
202  unsigned int b;
203 
204  if (a < 255) return (ff_sqrt_tab[a + 1] - 1) >> 4;
205  else if (a < (1 << 12)) b = ff_sqrt_tab[a >> 4] >> 2;
206 #if !CONFIG_SMALL
207  else if (a < (1 << 14)) b = ff_sqrt_tab[a >> 6] >> 1;
208  else if (a < (1 << 16)) b = ff_sqrt_tab[a >> 8] ;
209 #endif
210  else {
211  int s = av_log2_16bit(a >> 16) >> 1;
212  unsigned int c = a >> (s + 2);
213  b = ff_sqrt_tab[c >> (s + 8)];
214  b = FASTDIV(c,b) + (b << s);
215  }
216 
217  return b - (a < b * b);
218 }
219 
220 static inline int8_t ff_u8_to_s8(uint8_t a)
221 {
222  union {
223  uint8_t u8;
224  int8_t s8;
225  } b;
226  b.u8 = a;
227  return b.s8;
228 }
229 
230 #endif /* AVCODEC_MATHOPS_H */