Fix previously broken x86_64 check, simplifying it in the process.
[libav.git] / libavutil / mathematics.c
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1/*
2 * Copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at>
3 *
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4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
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7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
b78e7197 9 * version 2.1 of the License, or (at your option) any later version.
c11c2bc2 10 *
b78e7197 11 * FFmpeg is distributed in the hope that it will be useful,
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12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
b78e7197 17 * License along with FFmpeg; if not, write to the Free Software
5509bffa 18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
c11c2bc2 19 */
115329f1 20
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21/**
22 * @file mathematics.c
23 * Miscellaneous math routines and tables.
24 */
25
26#include "common.h"
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27#include "mathematics.h"
28
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29const uint8_t ff_sqrt_tab[256]={
30 0, 16, 23, 28, 32, 36, 40, 43, 46, 48, 51, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 77, 79, 80, 82, 84, 85, 87, 88, 90,
31 91, 92, 94, 95, 96, 98, 99,100,102,103,104,105,107,108,109,110,111,112,114,115,116,117,118,119,120,121,122,123,124,125,126,127,
32128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,144,145,146,147,148,149,150,151,151,152,153,154,155,156,156,
33157,158,159,160,160,161,162,163,164,164,165,166,167,168,168,169,170,171,171,172,173,174,174,175,176,176,177,178,179,179,180,181,
34182,182,183,184,184,185,186,186,187,188,188,189,190,190,191,192,192,193,194,194,195,196,196,197,198,198,199,200,200,201,202,202,
35203,204,204,205,205,206,207,207,208,208,209,210,210,211,212,212,213,213,214,215,215,216,216,217,218,218,219,219,220,220,221,222,
36222,223,223,224,224,225,226,226,227,227,228,228,229,230,230,231,231,232,232,233,233,234,235,235,236,236,237,237,238,238,239,239,
37240,240,241,242,242,243,243,244,244,245,245,246,246,247,247,248,248,249,249,250,250,251,251,252,252,253,253,254,254,255,255,255
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38};
39
40const uint8_t ff_log2_tab[256]={
41 0,0,1,1,2,2,2,2,3,3,3,3,3,3,3,3,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,
42 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
43 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
44 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
45 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
46 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
47 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
48 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7
49};
50
51int64_t ff_gcd(int64_t a, int64_t b){
52 if(b) return ff_gcd(b, a%b);
53 else return a;
54}
55
56int64_t av_rescale_rnd(int64_t a, int64_t b, int64_t c, enum AVRounding rnd){
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57 int64_t r=0;
58 assert(c > 0);
59 assert(b >=0);
60 assert(rnd >=0 && rnd<=5 && rnd!=4);
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61
62 if(a<0 && a != INT64_MIN) return -av_rescale_rnd(-a, b, c, rnd ^ ((rnd>>1)&1));
63
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64 if(rnd==AV_ROUND_NEAR_INF) r= c/2;
65 else if(rnd&1) r= c-1;
66
67 if(b<=INT_MAX && c<=INT_MAX){
68 if(a<=INT_MAX)
69 return (a * b + r)/c;
70 else
71 return a/c*b + (a%c*b + r)/c;
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72 }else{
73#if 1
74 uint64_t a0= a&0xFFFFFFFF;
75 uint64_t a1= a>>32;
76 uint64_t b0= b&0xFFFFFFFF;
77 uint64_t b1= b>>32;
78 uint64_t t1= a0*b1 + a1*b0;
79 uint64_t t1a= t1<<32;
80 int i;
81
82 a0 = a0*b0 + t1a;
83 a1 = a1*b1 + (t1>>32) + (a0<t1a);
84 a0 += r;
85 a1 += a0<r;
115329f1 86
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87 for(i=63; i>=0; i--){
88// int o= a1 & 0x8000000000000000ULL;
89 a1+= a1 + ((a0>>i)&1);
90 t1+=t1;
5c1cb379 91 if(/*o || */c <= a1){
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92 a1 -= c;
93 t1++;
94 }
95 }
96 return t1;
97 }
98#else
99 AVInteger ai;
100 ai= av_mul_i(av_int2i(a), av_int2i(b));
101 ai= av_add_i(ai, av_int2i(r));
115329f1 102
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103 return av_i2int(av_div_i(ai, av_int2i(c)));
104 }
105#endif
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106}
107
108int64_t av_rescale(int64_t a, int64_t b, int64_t c){
109 return av_rescale_rnd(a, b, c, AV_ROUND_NEAR_INF);
110}
111
112int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq){
113 int64_t b= bq.num * (int64_t)cq.den;
114 int64_t c= cq.num * (int64_t)bq.den;
115 return av_rescale_rnd(a, b, c, AV_ROUND_NEAR_INF);
116}
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117
118#ifdef TEST
fc861443 119#include "integer.h"
5c1cb379 120#undef printf
f3635240 121int main(void){
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122 int64_t a,b,c,d,e;
123
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124 for(a=7; a<(1LL<<62); a+=a/3+1){
125 for(b=3; b<(1LL<<62); b+=b/4+1){
126 for(c=9; c<(1LL<<62); c+=(c*2)/5+3){
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127 int64_t r= c/2;
128 AVInteger ai;
129 ai= av_mul_i(av_int2i(a), av_int2i(b));
130 ai= av_add_i(ai, av_int2i(r));
131
132 d= av_i2int(av_div_i(ai, av_int2i(c)));
133
134 e= av_rescale(a,b,c);
135
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136 if((double)a * (double)b / (double)c > (1LL<<63))
137 continue;
138
949b1a13 139 if(d!=e) printf("%"PRId64"*%"PRId64"/%"PRId64"= %"PRId64"=%"PRId64"\n", a, b, c, d, e);
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140 }
141 }
142 }
f3635240 143 return 0;
fdb3a341 144}
d1c9b762 145#endif