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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 4349 | Serge | 1 | /* |
| 2 | * Copyright (c) 2006 Michael Niedermayer |
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| 3 | * |
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| 4 | * This file is part of FFmpeg. |
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| 5 | * |
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| 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 |
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| 8 | * License as published by the Free Software Foundation; either |
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| 9 | * version 2.1 of the License, or (at your option) any later version. |
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| 10 | * |
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| 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 |
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| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 14 | * Lesser General Public License for more details. |
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| 15 | * |
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| 16 | * You should have received a copy of the GNU Lesser General Public |
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| 17 | * License along with FFmpeg; if not, write to the Free Software |
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| 18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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| 19 | */ |
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| 20 | |||
| 21 | #ifndef AVUTIL_SOFTFLOAT_H |
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| 22 | #define AVUTIL_SOFTFLOAT_H |
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| 23 | |||
| 24 | #include |
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| 25 | #include "common.h" |
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| 26 | |||
| 27 | #define MIN_EXP -126 |
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| 28 | #define MAX_EXP 126 |
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| 29 | #define ONE_BITS 29 |
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| 30 | |||
| 31 | typedef struct SoftFloat{ |
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| 32 | int32_t exp; |
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| 33 | int32_t mant; |
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| 34 | }SoftFloat; |
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| 35 | |||
| 36 | static av_const SoftFloat av_normalize_sf(SoftFloat a){ |
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| 37 | if(a.mant){ |
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| 38 | #if 1 |
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| 39 | while((a.mant + 0x20000000U)<0x40000000U){ |
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| 40 | a.mant += a.mant; |
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| 41 | a.exp -= 1; |
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| 42 | } |
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| 43 | #else |
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| 44 | int s=ONE_BITS + 1 - av_log2(a.mant ^ (a.mant<<1)); |
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| 45 | a.exp -= s; |
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| 46 | a.mant <<= s; |
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| 47 | #endif |
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| 48 | if(a.exp < MIN_EXP){ |
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| 49 | a.exp = MIN_EXP; |
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| 50 | a.mant= 0; |
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| 51 | } |
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| 52 | }else{ |
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| 53 | a.exp= MIN_EXP; |
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| 54 | } |
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| 55 | return a; |
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| 56 | } |
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| 57 | |||
| 58 | static inline av_const SoftFloat av_normalize1_sf(SoftFloat a){ |
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| 59 | #if 1 |
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| 60 | if(a.mant + 0x40000000 < 0){ |
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| 61 | a.exp++; |
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| 62 | a.mant>>=1; |
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| 63 | } |
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| 64 | return a; |
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| 65 | #elif 1 |
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| 66 | int t= a.mant + 0x40000000 < 0; |
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| 67 | return (SoftFloat){a.exp+t, a.mant>>t}; |
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| 68 | #else |
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| 69 | int t= (a.mant + 0x40000000U)>>31; |
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| 70 | return (SoftFloat){a.exp+t, a.mant>>t}; |
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| 71 | #endif |
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| 72 | } |
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| 73 | |||
| 74 | /** |
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| 75 | * @return Will not be more denormalized than a+b. So if either input is |
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| 76 | * normalized, then the output will not be worse then the other input. |
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| 77 | * If both are normalized, then the output will be normalized. |
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| 78 | */ |
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| 79 | static inline av_const SoftFloat av_mul_sf(SoftFloat a, SoftFloat b){ |
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| 80 | a.exp += b.exp; |
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| 81 | a.mant = (a.mant * (int64_t)b.mant) >> ONE_BITS; |
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| 82 | return av_normalize1_sf(a); |
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| 83 | } |
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| 84 | |||
| 85 | /** |
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| 86 | * b has to be normalized and not zero. |
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| 87 | * @return Will not be more denormalized than a. |
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| 88 | */ |
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| 89 | static av_const SoftFloat av_div_sf(SoftFloat a, SoftFloat b){ |
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| 90 | a.exp -= b.exp+1; |
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| 91 | a.mant = ((int64_t)a.mant<<(ONE_BITS+1)) / b.mant; |
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| 92 | return av_normalize1_sf(a); |
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| 93 | } |
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| 94 | |||
| 95 | static inline av_const int av_cmp_sf(SoftFloat a, SoftFloat b){ |
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| 96 | int t= a.exp - b.exp; |
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| 97 | if(t<0) return (a.mant >> (-t)) - b.mant ; |
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| 98 | else return a.mant - (b.mant >> t); |
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| 99 | } |
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| 100 | |||
| 101 | static inline av_const SoftFloat av_add_sf(SoftFloat a, SoftFloat b){ |
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| 102 | int t= a.exp - b.exp; |
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| 103 | if(t<0) return av_normalize1_sf((SoftFloat){b.exp, b.mant + (a.mant >> (-t))}); |
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| 104 | else return av_normalize1_sf((SoftFloat){a.exp, a.mant + (b.mant >> t )}); |
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| 105 | } |
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| 106 | |||
| 107 | static inline av_const SoftFloat av_sub_sf(SoftFloat a, SoftFloat b){ |
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| 108 | return av_add_sf(a, (SoftFloat){b.exp, -b.mant}); |
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| 109 | } |
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| 110 | |||
| 111 | //FIXME sqrt, log, exp, pow, sin, cos |
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| 112 | |||
| 113 | static inline av_const SoftFloat av_int2sf(int v, int frac_bits){ |
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| 114 | return av_normalize_sf((SoftFloat){ONE_BITS-frac_bits, v}); |
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| 115 | } |
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| 116 | |||
| 117 | /** |
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| 118 | * Rounding is to -inf. |
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| 119 | */ |
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| 120 | static inline av_const int av_sf2int(SoftFloat v, int frac_bits){ |
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| 121 | v.exp += frac_bits - ONE_BITS; |
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| 122 | if(v.exp >= 0) return v.mant << v.exp ; |
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| 123 | else return v.mant >>(-v.exp); |
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| 124 | } |
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| 125 | |||
| 126 | #endif /* AVUTIL_SOFTFLOAT_H */ |