LCOV - code coverage report
Current view: top level - libavutil - softfloat.h (source / functions) Hit Total Coverage
Test: coverage.info Lines: 94 103 91.3 %
Date: 2017-12-15 02:19:58 Functions: 10 10 100.0 %

          Line data    Source code
       1             : /*
       2             :  * Copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
       3             :  *
       4             :  * This file is part of FFmpeg.
       5             :  *
       6             :  * FFmpeg is free software; you can redistribute it and/or
       7             :  * modify it under the terms of the GNU Lesser General Public
       8             :  * License as published by the Free Software Foundation; either
       9             :  * version 2.1 of the License, or (at your option) any later version.
      10             :  *
      11             :  * FFmpeg is distributed in the hope that it will be useful,
      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
      17             :  * License along with FFmpeg; if not, write to the Free Software
      18             :  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
      19             :  */
      20             : 
      21             : #ifndef AVUTIL_SOFTFLOAT_H
      22             : #define AVUTIL_SOFTFLOAT_H
      23             : 
      24             : #include <stdint.h>
      25             : #include "common.h"
      26             : 
      27             : #include "avassert.h"
      28             : #include "softfloat_tables.h"
      29             : 
      30             : #define MIN_EXP -149
      31             : #define MAX_EXP  126
      32             : #define ONE_BITS 29
      33             : 
      34             : typedef struct SoftFloat{
      35             :     int32_t mant;
      36             :     int32_t  exp;
      37             : }SoftFloat;
      38             : 
      39             : static const SoftFloat FLOAT_0          = {          0,   MIN_EXP};             ///< 0.0
      40             : static const SoftFloat FLOAT_05         = { 0x20000000,   0};                   ///< 0.5
      41             : static const SoftFloat FLOAT_1          = { 0x20000000,   1};                   ///< 1.0
      42             : static const SoftFloat FLOAT_EPSILON    = { 0x29F16B12, -16};                   ///< A small value
      43             : static const SoftFloat FLOAT_1584893192 = { 0x32B771ED,   1};                   ///< 1.584893192 (10^.2)
      44             : static const SoftFloat FLOAT_100000     = { 0x30D40000,  17};                   ///< 100000
      45             : static const SoftFloat FLOAT_0999999    = { 0x3FFFFBCE,   0};                   ///< 0.999999
      46             : static const SoftFloat FLOAT_MIN        = { 0x20000000,   MIN_EXP};
      47             : 
      48             : 
      49             : /**
      50             :  * Convert a SoftFloat to a double precision float.
      51             :  */
      52             : static inline av_const double av_sf2double(SoftFloat v) {
      53             :     v.exp -= ONE_BITS +1;
      54             :     return ldexp(v.mant, v.exp);
      55             : }
      56             : 
      57     8668843 : static av_const SoftFloat av_normalize_sf(SoftFloat a){
      58     8668843 :     if(a.mant){
      59             : #if 1
      60    19620769 :         while((a.mant + 0x1FFFFFFFU)<0x3FFFFFFFU){
      61     2591711 :             a.mant += a.mant;
      62     2591711 :             a.exp  -= 1;
      63             :         }
      64             : #else
      65             :         int s=ONE_BITS - av_log2(FFABS(a.mant));
      66             :         a.exp   -= s;
      67             :         a.mant <<= s;
      68             : #endif
      69     8514529 :         if(a.exp < MIN_EXP){
      70           0 :             a.exp = MIN_EXP;
      71           0 :             a.mant= 0;
      72             :         }
      73             :     }else{
      74      154314 :         a.exp= MIN_EXP;
      75             :     }
      76     8668843 :     return a;
      77             : }
      78             : 
      79    18107100 : static inline av_const SoftFloat av_normalize1_sf(SoftFloat a){
      80             : #if 1
      81    18107100 :     if((int32_t)(a.mant + 0x40000000U) <= 0){
      82     6405761 :         a.exp++;
      83     6405761 :         a.mant>>=1;
      84             :     }
      85             :     av_assert2(a.mant < 0x40000000 && a.mant > -0x40000000);
      86             :     av_assert2(a.exp <= MAX_EXP);
      87    18107100 :     return a;
      88             : #elif 1
      89             :     int t= a.mant + 0x40000000 < 0;
      90             :     return (SoftFloat){ a.mant>>t, a.exp+t};
      91             : #else
      92             :     int t= (a.mant + 0x3FFFFFFFU)>>31;
      93             :     return (SoftFloat){a.mant>>t, a.exp+t};
      94             : #endif
      95             : }
      96             : 
      97             : /**
      98             :  * @return Will not be more denormalized than a*b. So if either input is
      99             :  *         normalized, then the output will not be worse then the other input.
     100             :  *         If both are normalized, then the output will be normalized.
     101             :  */
     102     8724021 : static inline av_const SoftFloat av_mul_sf(SoftFloat a, SoftFloat b){
     103     8724021 :     a.exp += b.exp;
     104             :     av_assert2((int32_t)((a.mant * (int64_t)b.mant) >> ONE_BITS) == (a.mant * (int64_t)b.mant) >> ONE_BITS);
     105     8724021 :     a.mant = (a.mant * (int64_t)b.mant) >> ONE_BITS;
     106     8724021 :     a = av_normalize1_sf((SoftFloat){a.mant, a.exp - 1});
     107     8724021 :     if (!a.mant || a.exp < MIN_EXP)
     108      397660 :         return FLOAT_0;
     109     8326361 :     return a;
     110             : }
     111             : 
     112             : /**
     113             :  * b has to be normalized and not zero.
     114             :  * @return Will not be more denormalized than a.
     115             :  */
     116      714236 : static inline av_const SoftFloat av_div_sf(SoftFloat a, SoftFloat b){
     117      714236 :     int64_t temp = (int64_t)a.mant * (1<<(ONE_BITS+1));
     118      714236 :     temp /= b.mant;
     119      714236 :     a.exp -= b.exp;
     120      714236 :     a.mant = temp;
     121     1428472 :     while (a.mant != temp) {
     122           0 :         temp /= 2;
     123           0 :         a.exp--;
     124           0 :         a.mant = temp;
     125             :     }
     126      714236 :     a = av_normalize1_sf(a);
     127      714236 :     if (!a.mant || a.exp < MIN_EXP)
     128        1507 :         return FLOAT_0;
     129      712729 :     return a;
     130             : }
     131             : 
     132             : /**
     133             :  * Compares two SoftFloats.
     134             :  * @returns < 0 if the first is less
     135             :  *          > 0 if the first is greater
     136             :  *            0 if they are equal
     137             :  */
     138             : static inline av_const int av_cmp_sf(SoftFloat a, SoftFloat b){
     139             :     int t= a.exp - b.exp;
     140             :     if      (t <-31) return                  -  b.mant      ;
     141             :     else if (t <  0) return (a.mant >> (-t)) -  b.mant      ;
     142             :     else if (t < 32) return  a.mant          - (b.mant >> t);
     143             :     else             return  a.mant                         ;
     144             : }
     145             : 
     146             : /**
     147             :  * Compares two SoftFloats.
     148             :  * @returns 1 if a is greater than b, 0 otherwise
     149             :  */
     150      291082 : static inline av_const int av_gt_sf(SoftFloat a, SoftFloat b)
     151             : {
     152      291082 :     int t= a.exp - b.exp;
     153      291082 :     if      (t <-31) return 0                >  b.mant      ;
     154      291082 :     else if (t <  0) return (a.mant >> (-t)) >  b.mant      ;
     155      127210 :     else if (t < 32) return  a.mant          > (b.mant >> t);
     156           0 :     else             return  a.mant          >  0           ;
     157             : }
     158             : 
     159             : /**
     160             :  * @returns the sum of 2 SoftFloats.
     161             :  */
     162     8247851 : static inline av_const SoftFloat av_add_sf(SoftFloat a, SoftFloat b){
     163     8247851 :     int t= a.exp - b.exp;
     164     8247851 :     if      (t <-31) return b;
     165     8113458 :     else if (t <  0) return av_normalize_sf(av_normalize1_sf((SoftFloat){ b.mant + (a.mant >> (-t)), b.exp}));
     166     7080051 :     else if (t < 32) return av_normalize_sf(av_normalize1_sf((SoftFloat){ a.mant + (b.mant >>   t ), a.exp}));
     167      258853 :     else             return a;
     168             : }
     169             : 
     170             : /**
     171             :  * @returns the difference of 2 SoftFloats.
     172             :  */
     173      333658 : static inline av_const SoftFloat av_sub_sf(SoftFloat a, SoftFloat b){
     174      333658 :     return av_add_sf(a, (SoftFloat){ -b.mant, b.exp});
     175             : }
     176             : 
     177             : //FIXME log, exp, pow
     178             : 
     179             : /**
     180             :  * Converts a mantisse and exponent to a SoftFloat.
     181             :  * This converts a fixed point value v with frac_bits fractional bits to a
     182             :  * SoftFloat.
     183             :  * @returns a SoftFloat with value v * 2^-frac_bits
     184             :  */
     185      814238 : static inline av_const SoftFloat av_int2sf(int v, int frac_bits){
     186      814238 :     int exp_offset = 0;
     187      814238 :     if(v <= INT_MIN + 1){
     188           0 :         exp_offset = 1;
     189           0 :         v>>=1;
     190             :     }
     191      814238 :     return av_normalize_sf(av_normalize1_sf((SoftFloat){v, ONE_BITS + 1 - frac_bits + exp_offset}));
     192             : }
     193             : 
     194             : /**
     195             :  * Converts a SoftFloat to an integer.
     196             :  * Rounding is to -inf.
     197             :  */
     198             : static inline av_const int av_sf2int(SoftFloat v, int frac_bits){
     199             :     v.exp += frac_bits - (ONE_BITS + 1);
     200             :     if(v.exp >= 0) return v.mant <<  v.exp ;
     201             :     else           return v.mant >>(-v.exp);
     202             : }
     203             : 
     204             : /**
     205             :  * Rounding-to-nearest used.
     206             :  */
     207      427111 : static av_always_inline SoftFloat av_sqrt_sf(SoftFloat val)
     208             : {
     209             :     int tabIndex, rem;
     210             : 
     211      427111 :     if (val.mant == 0)
     212      126160 :         val.exp = MIN_EXP;
     213      300951 :     else if (val.mant < 0)
     214           0 :         abort();
     215             :     else
     216             :     {
     217      300951 :         tabIndex = (val.mant - 0x20000000) >> 20;
     218             : 
     219      300951 :         rem = val.mant & 0xFFFFF;
     220      902853 :         val.mant  = (int)(((int64_t)av_sqrttbl_sf[tabIndex] * (0x100000 - rem) +
     221      601902 :                            (int64_t)av_sqrttbl_sf[tabIndex + 1] * rem +
     222      300951 :                            0x80000) >> 20);
     223      601902 :         val.mant = (int)(((int64_t)av_sqr_exp_multbl_sf[val.exp & 1] * val.mant +
     224      300951 :                           0x10000000) >> 29);
     225             : 
     226      300951 :         if (val.mant < 0x40000000)
     227      143247 :             val.exp -= 2;
     228             :         else
     229      157704 :             val.mant >>= 1;
     230             : 
     231      300951 :         val.exp = (val.exp >> 1) + 1;
     232             :     }
     233             : 
     234      427111 :     return val;
     235             : }
     236             : 
     237             : /**
     238             :  * Rounding-to-nearest used.
     239             :  */
     240       28672 : static av_unused void av_sincos_sf(int a, int *s, int *c)
     241             : {
     242             :     int idx, sign;
     243             :     int sv, cv;
     244             :     int st, ct;
     245             : 
     246       28672 :     idx = a >> 26;
     247       28672 :     sign = (int32_t)((unsigned)idx << 27) >> 31;
     248       28672 :     cv = av_costbl_1_sf[idx & 0xf];
     249       28672 :     cv = (cv ^ sign) - sign;
     250             : 
     251       28672 :     idx -= 8;
     252       28672 :     sign = (int32_t)((unsigned)idx << 27) >> 31;
     253       28672 :     sv = av_costbl_1_sf[idx & 0xf];
     254       28672 :     sv = (sv ^ sign) - sign;
     255             : 
     256       28672 :     idx = a >> 21;
     257       28672 :     ct = av_costbl_2_sf[idx & 0x1f];
     258       28672 :     st = av_sintbl_2_sf[idx & 0x1f];
     259             : 
     260       28672 :     idx = (int)(((int64_t)cv * ct - (int64_t)sv * st + 0x20000000) >> 30);
     261             : 
     262       28672 :     sv = (int)(((int64_t)cv * st + (int64_t)sv * ct + 0x20000000) >> 30);
     263             : 
     264       28672 :     cv = idx;
     265             : 
     266       28672 :     idx = a >> 16;
     267       28672 :     ct = av_costbl_3_sf[idx & 0x1f];
     268       28672 :     st = av_sintbl_3_sf[idx & 0x1f];
     269             : 
     270       28672 :     idx = (int)(((int64_t)cv * ct - (int64_t)sv * st + 0x20000000) >> 30);
     271             : 
     272       28672 :     sv = (int)(((int64_t)cv * st + (int64_t)sv * ct + 0x20000000) >> 30);
     273       28672 :     cv = idx;
     274             : 
     275       28672 :     idx = a >> 11;
     276             : 
     277       86016 :     ct = (int)(((int64_t)av_costbl_4_sf[idx & 0x1f] * (0x800 - (a & 0x7ff)) +
     278       57344 :                 (int64_t)av_costbl_4_sf[(idx & 0x1f)+1]*(a & 0x7ff) +
     279       28672 :                 0x400) >> 11);
     280       86016 :     st = (int)(((int64_t)av_sintbl_4_sf[idx & 0x1f] * (0x800 - (a & 0x7ff)) +
     281       57344 :                 (int64_t)av_sintbl_4_sf[(idx & 0x1f) + 1] * (a & 0x7ff) +
     282       28672 :                 0x400) >> 11);
     283             : 
     284       28672 :     *c = (int)(((int64_t)cv * ct + (int64_t)sv * st + 0x20000000) >> 30);
     285             : 
     286       28672 :     *s = (int)(((int64_t)cv * st + (int64_t)sv * ct + 0x20000000) >> 30);
     287       28672 : }
     288             : 
     289             : #endif /* AVUTIL_SOFTFLOAT_H */

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