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: 2017-10-20 23:03:07 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             : 
      47             : 
      48             : /**
      49             :  * Convert a SoftFloat to a double precision float.
      50             :  */
      51             : static inline av_const double av_sf2double(SoftFloat v) {
      52             :     v.exp -= ONE_BITS +1;
      53             :     return ldexp(v.mant, v.exp);
      54             : }
      55             : 
      56     8668331 : static av_const SoftFloat av_normalize_sf(SoftFloat a){
      57     8668331 :     if(a.mant){
      58             : #if 1
      59    19618977 :         while((a.mant + 0x1FFFFFFFU)<0x3FFFFFFFU){
      60     2590943 :             a.mant += a.mant;
      61     2590943 :             a.exp  -= 1;
      62             :         }
      63             : #else
      64             :         int s=ONE_BITS - av_log2(FFABS(a.mant));
      65             :         a.exp   -= s;
      66             :         a.mant <<= s;
      67             : #endif
      68     8514017 :         if(a.exp < MIN_EXP){
      69           0 :             a.exp = MIN_EXP;
      70           0 :             a.mant= 0;
      71             :         }
      72             :     }else{
      73      154314 :         a.exp= MIN_EXP;
      74             :     }
      75     8668331 :     return a;
      76             : }
      77             : 
      78    18106076 : static inline av_const SoftFloat av_normalize1_sf(SoftFloat a){
      79             : #if 1
      80    18106076 :     if((int32_t)(a.mant + 0x40000000U) <= 0){
      81     6405753 :         a.exp++;
      82     6405753 :         a.mant>>=1;
      83             :     }
      84             :     av_assert2(a.mant < 0x40000000 && a.mant > -0x40000000);
      85             :     av_assert2(a.exp <= MAX_EXP);
      86    18106076 :     return a;
      87             : #elif 1
      88             :     int t= a.mant + 0x40000000 < 0;
      89             :     return (SoftFloat){ a.mant>>t, a.exp+t};
      90             : #else
      91             :     int t= (a.mant + 0x3FFFFFFFU)>>31;
      92             :     return (SoftFloat){a.mant>>t, a.exp+t};
      93             : #endif
      94             : }
      95             : 
      96             : /**
      97             :  * @return Will not be more denormalized than a*b. So if either input is
      98             :  *         normalized, then the output will not be worse then the other input.
      99             :  *         If both are normalized, then the output will be normalized.
     100             :  */
     101     8724021 : static inline av_const SoftFloat av_mul_sf(SoftFloat a, SoftFloat b){
     102     8724021 :     a.exp += b.exp;
     103             :     av_assert2((int32_t)((a.mant * (int64_t)b.mant) >> ONE_BITS) == (a.mant * (int64_t)b.mant) >> ONE_BITS);
     104     8724021 :     a.mant = (a.mant * (int64_t)b.mant) >> ONE_BITS;
     105     8724021 :     a = av_normalize1_sf((SoftFloat){a.mant, a.exp - 1});
     106     8724021 :     if (!a.mant || a.exp < MIN_EXP)
     107      397660 :         return FLOAT_0;
     108     8326361 :     return a;
     109             : }
     110             : 
     111             : /**
     112             :  * b has to be normalized and not zero.
     113             :  * @return Will not be more denormalized than a.
     114             :  */
     115      713724 : static inline av_const SoftFloat av_div_sf(SoftFloat a, SoftFloat b){
     116      713724 :     int64_t temp = (int64_t)a.mant * (1<<(ONE_BITS+1));
     117      713724 :     temp /= b.mant;
     118      713724 :     a.exp -= b.exp;
     119      713724 :     a.mant = temp;
     120     1427448 :     while (a.mant != temp) {
     121           0 :         temp /= 2;
     122           0 :         a.exp--;
     123           0 :         a.mant = temp;
     124             :     }
     125      713724 :     a = av_normalize1_sf(a);
     126      713724 :     if (!a.mant || a.exp < MIN_EXP)
     127        1507 :         return FLOAT_0;
     128      712217 :     return a;
     129             : }
     130             : 
     131             : /**
     132             :  * Compares two SoftFloats.
     133             :  * @returns < 0 if the first is less
     134             :  *          > 0 if the first is greater
     135             :  *            0 if they are equal
     136             :  */
     137             : static inline av_const int av_cmp_sf(SoftFloat a, SoftFloat b){
     138             :     int t= a.exp - b.exp;
     139             :     if      (t <-31) return                  -  b.mant      ;
     140             :     else if (t <  0) return (a.mant >> (-t)) -  b.mant      ;
     141             :     else if (t < 32) return  a.mant          - (b.mant >> t);
     142             :     else             return  a.mant                         ;
     143             : }
     144             : 
     145             : /**
     146             :  * Compares two SoftFloats.
     147             :  * @returns 1 if a is greater than b, 0 otherwise
     148             :  */
     149      291082 : static inline av_const int av_gt_sf(SoftFloat a, SoftFloat b)
     150             : {
     151      291082 :     int t= a.exp - b.exp;
     152      291082 :     if      (t <-31) return 0                >  b.mant      ;
     153      291082 :     else if (t <  0) return (a.mant >> (-t)) >  b.mant      ;
     154      127210 :     else if (t < 32) return  a.mant          > (b.mant >> t);
     155           0 :     else             return  a.mant          >  0           ;
     156             : }
     157             : 
     158             : /**
     159             :  * @returns the sum of 2 SoftFloats.
     160             :  */
     161     8120014 : static inline av_const SoftFloat av_add_sf(SoftFloat a, SoftFloat b){
     162     8120014 :     int t= a.exp - b.exp;
     163     8120014 :     if      (t <-31) return b;
     164     7985621 :     else if (t <  0) return av_normalize_sf(av_normalize1_sf((SoftFloat){ b.mant + (a.mant >> (-t)), b.exp}));
     165     6952214 :     else if (t < 32) return av_normalize_sf(av_normalize1_sf((SoftFloat){ a.mant + (b.mant >>   t ), a.exp}));
     166      131016 :     else             return a;
     167             : }
     168             : 
     169             : /**
     170             :  * @returns the difference of 2 SoftFloats.
     171             :  */
     172      333658 : static inline av_const SoftFloat av_sub_sf(SoftFloat a, SoftFloat b){
     173      333658 :     return av_add_sf(a, (SoftFloat){ -b.mant, b.exp});
     174             : }
     175             : 
     176             : //FIXME log, exp, pow
     177             : 
     178             : /**
     179             :  * Converts a mantisse and exponent to a SoftFloat.
     180             :  * This converts a fixed point value v with frac_bits fractional bits to a
     181             :  * SoftFloat.
     182             :  * @returns a SoftFloat with value v * 2^-frac_bits
     183             :  */
     184      813726 : static inline av_const SoftFloat av_int2sf(int v, int frac_bits){
     185      813726 :     int exp_offset = 0;
     186      813726 :     if(v <= INT_MIN + 1){
     187           0 :         exp_offset = 1;
     188           0 :         v>>=1;
     189             :     }
     190      813726 :     return av_normalize_sf(av_normalize1_sf((SoftFloat){v, ONE_BITS + 1 - frac_bits + exp_offset}));
     191             : }
     192             : 
     193             : /**
     194             :  * Converts a SoftFloat to an integer.
     195             :  * Rounding is to -inf.
     196             :  */
     197             : static inline av_const int av_sf2int(SoftFloat v, int frac_bits){
     198             :     v.exp += frac_bits - (ONE_BITS + 1);
     199             :     if(v.exp >= 0) return v.mant <<  v.exp ;
     200             :     else           return v.mant >>(-v.exp);
     201             : }
     202             : 
     203             : /**
     204             :  * Rounding-to-nearest used.
     205             :  */
     206      426599 : static av_always_inline SoftFloat av_sqrt_sf(SoftFloat val)
     207             : {
     208             :     int tabIndex, rem;
     209             : 
     210      426599 :     if (val.mant == 0)
     211      126160 :         val.exp = MIN_EXP;
     212      300439 :     else if (val.mant < 0)
     213           0 :         abort();
     214             :     else
     215             :     {
     216      300439 :         tabIndex = (val.mant - 0x20000000) >> 20;
     217             : 
     218      300439 :         rem = val.mant & 0xFFFFF;
     219      901317 :         val.mant  = (int)(((int64_t)av_sqrttbl_sf[tabIndex] * (0x100000 - rem) +
     220      600878 :                            (int64_t)av_sqrttbl_sf[tabIndex + 1] * rem +
     221      300439 :                            0x80000) >> 20);
     222      600878 :         val.mant = (int)(((int64_t)av_sqr_exp_multbl_sf[val.exp & 1] * val.mant +
     223      300439 :                           0x10000000) >> 29);
     224             : 
     225      300439 :         if (val.mant < 0x40000000)
     226      143007 :             val.exp -= 2;
     227             :         else
     228      157432 :             val.mant >>= 1;
     229             : 
     230      300439 :         val.exp = (val.exp >> 1) + 1;
     231             :     }
     232             : 
     233      426599 :     return val;
     234             : }
     235             : 
     236             : /**
     237             :  * Rounding-to-nearest used.
     238             :  */
     239       26880 : static av_unused void av_sincos_sf(int a, int *s, int *c)
     240             : {
     241             :     int idx, sign;
     242             :     int sv, cv;
     243             :     int st, ct;
     244             : 
     245       26880 :     idx = a >> 26;
     246       26880 :     sign = (int32_t)((unsigned)idx << 27) >> 31;
     247       26880 :     cv = av_costbl_1_sf[idx & 0xf];
     248       26880 :     cv = (cv ^ sign) - sign;
     249             : 
     250       26880 :     idx -= 8;
     251       26880 :     sign = (int32_t)((unsigned)idx << 27) >> 31;
     252       26880 :     sv = av_costbl_1_sf[idx & 0xf];
     253       26880 :     sv = (sv ^ sign) - sign;
     254             : 
     255       26880 :     idx = a >> 21;
     256       26880 :     ct = av_costbl_2_sf[idx & 0x1f];
     257       26880 :     st = av_sintbl_2_sf[idx & 0x1f];
     258             : 
     259       26880 :     idx = (int)(((int64_t)cv * ct - (int64_t)sv * st + 0x20000000) >> 30);
     260             : 
     261       26880 :     sv = (int)(((int64_t)cv * st + (int64_t)sv * ct + 0x20000000) >> 30);
     262             : 
     263       26880 :     cv = idx;
     264             : 
     265       26880 :     idx = a >> 16;
     266       26880 :     ct = av_costbl_3_sf[idx & 0x1f];
     267       26880 :     st = av_sintbl_3_sf[idx & 0x1f];
     268             : 
     269       26880 :     idx = (int)(((int64_t)cv * ct - (int64_t)sv * st + 0x20000000) >> 30);
     270             : 
     271       26880 :     sv = (int)(((int64_t)cv * st + (int64_t)sv * ct + 0x20000000) >> 30);
     272       26880 :     cv = idx;
     273             : 
     274       26880 :     idx = a >> 11;
     275             : 
     276       80640 :     ct = (int)(((int64_t)av_costbl_4_sf[idx & 0x1f] * (0x800 - (a & 0x7ff)) +
     277       53760 :                 (int64_t)av_costbl_4_sf[(idx & 0x1f)+1]*(a & 0x7ff) +
     278       26880 :                 0x400) >> 11);
     279       80640 :     st = (int)(((int64_t)av_sintbl_4_sf[idx & 0x1f] * (0x800 - (a & 0x7ff)) +
     280       53760 :                 (int64_t)av_sintbl_4_sf[(idx & 0x1f) + 1] * (a & 0x7ff) +
     281       26880 :                 0x400) >> 11);
     282             : 
     283       26880 :     *c = (int)(((int64_t)cv * ct + (int64_t)sv * st + 0x20000000) >> 30);
     284             : 
     285       26880 :     *s = (int)(((int64_t)cv * st + (int64_t)sv * ct + 0x20000000) >> 30);
     286       26880 : }
     287             : 
     288             : #endif /* AVUTIL_SOFTFLOAT_H */

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