| /* |
| * Copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at> |
| * |
| * This file is part of FFmpeg. |
| * |
| * FFmpeg is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2.1 of the License, or (at your option) any later version. |
| * |
| * FFmpeg is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with FFmpeg; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| #ifndef AVUTIL_SOFTFLOAT_H |
| #define AVUTIL_SOFTFLOAT_H |
| |
| #include <stdint.h> |
| #include "common.h" |
| |
| #include "avassert.h" |
| #include "softfloat_tables.h" |
| |
| #define MIN_EXP -126 |
| #define MAX_EXP 126 |
| #define ONE_BITS 29 |
| |
| typedef struct SoftFloat{ |
| int32_t mant; |
| int32_t exp; |
| }SoftFloat; |
| |
| static av_const SoftFloat av_normalize_sf(SoftFloat a){ |
| if(a.mant){ |
| #if 1 |
| while((a.mant + 0x1FFFFFFFU)<0x3FFFFFFFU){ |
| a.mant += a.mant; |
| a.exp -= 1; |
| } |
| #else |
| int s=ONE_BITS - av_log2(FFABS(a.mant)); |
| a.exp -= s; |
| a.mant <<= s; |
| #endif |
| if(a.exp < MIN_EXP){ |
| a.exp = MIN_EXP; |
| a.mant= 0; |
| } |
| }else{ |
| a.exp= MIN_EXP; |
| } |
| return a; |
| } |
| |
| static inline av_const SoftFloat av_normalize1_sf(SoftFloat a){ |
| #if 1 |
| if((int32_t)(a.mant + 0x40000000U) <= 0){ |
| a.exp++; |
| a.mant>>=1; |
| } |
| av_assert2(a.mant < 0x40000000 && a.mant > -0x40000000); |
| return a; |
| #elif 1 |
| int t= a.mant + 0x40000000 < 0; |
| return (SoftFloat){ a.mant>>t, a.exp+t}; |
| #else |
| int t= (a.mant + 0x3FFFFFFFU)>>31; |
| return (SoftFloat){a.mant>>t, a.exp+t}; |
| #endif |
| } |
| |
| /** |
| * @return Will not be more denormalized than a+b. So if either input is |
| * normalized, then the output will not be worse then the other input. |
| * If both are normalized, then the output will be normalized. |
| */ |
| static inline av_const SoftFloat av_mul_sf(SoftFloat a, SoftFloat b){ |
| a.exp += b.exp; |
| av_assert2((int32_t)((a.mant * (int64_t)b.mant) >> ONE_BITS) == (a.mant * (int64_t)b.mant) >> ONE_BITS); |
| a.mant = (a.mant * (int64_t)b.mant) >> ONE_BITS; |
| return av_normalize1_sf((SoftFloat){a.mant, a.exp - 1}); |
| } |
| |
| /** |
| * b has to be normalized and not zero. |
| * @return Will not be more denormalized than a. |
| */ |
| static av_const SoftFloat av_div_sf(SoftFloat a, SoftFloat b){ |
| a.exp -= b.exp; |
| a.mant = ((int64_t)a.mant<<(ONE_BITS+1)) / b.mant; |
| return av_normalize1_sf(a); |
| } |
| |
| static inline av_const int av_cmp_sf(SoftFloat a, SoftFloat b){ |
| int t= a.exp - b.exp; |
| if(t<0) return (a.mant >> (-t)) - b.mant ; |
| else return a.mant - (b.mant >> t); |
| } |
| |
| static inline av_const int av_gt_sf(SoftFloat a, SoftFloat b) |
| { |
| int t= a.exp - b.exp; |
| if(t<0) return (a.mant >> (-t)) > b.mant ; |
| else return a.mant > (b.mant >> t); |
| } |
| |
| static inline av_const SoftFloat av_add_sf(SoftFloat a, SoftFloat b){ |
| int t= a.exp - b.exp; |
| if (t <-31) return b; |
| else if (t < 0) return av_normalize_sf(av_normalize1_sf((SoftFloat){ b.mant + (a.mant >> (-t)), b.exp})); |
| else if (t < 32) return av_normalize_sf(av_normalize1_sf((SoftFloat){ a.mant + (b.mant >> t ), a.exp})); |
| else return a; |
| } |
| |
| static inline av_const SoftFloat av_sub_sf(SoftFloat a, SoftFloat b){ |
| return av_add_sf(a, (SoftFloat){ -b.mant, b.exp}); |
| } |
| |
| //FIXME log, exp, pow |
| |
| /** |
| * Converts a mantisse and exponent to a SoftFloat |
| * @returns a SoftFloat with value v * 2^frac_bits |
| */ |
| static inline av_const SoftFloat av_int2sf(int v, int frac_bits){ |
| return av_normalize_sf((SoftFloat){v, ONE_BITS + 1 - frac_bits}); |
| } |
| |
| /** |
| * Rounding is to -inf. |
| */ |
| static inline av_const int av_sf2int(SoftFloat v, int frac_bits){ |
| v.exp += frac_bits - (ONE_BITS + 1); |
| if(v.exp >= 0) return v.mant << v.exp ; |
| else return v.mant >>(-v.exp); |
| } |
| |
| /** |
| * Rounding-to-nearest used. |
| */ |
| static av_always_inline SoftFloat av_sqrt_sf(SoftFloat val) |
| { |
| int tabIndex, rem; |
| |
| if (val.mant == 0) |
| val.exp = 0; |
| else |
| { |
| tabIndex = (val.mant - 0x20000000) >> 20; |
| |
| rem = val.mant & 0xFFFFF; |
| val.mant = (int)(((int64_t)av_sqrttbl_sf[tabIndex] * (0x100000 - rem) + |
| (int64_t)av_sqrttbl_sf[tabIndex + 1] * rem + |
| 0x80000) >> 20); |
| val.mant = (int)(((int64_t)av_sqr_exp_multbl_sf[val.exp & 1] * val.mant + |
| 0x10000000) >> 29); |
| |
| if (val.mant < 0x40000000) |
| val.exp -= 2; |
| else |
| val.mant >>= 1; |
| |
| val.exp = (val.exp >> 1) + 1; |
| } |
| |
| return val; |
| } |
| |
| /** |
| * Rounding-to-nearest used. |
| */ |
| void av_sincos_sf(int a, int *s, int *c); |
| |
| #endif /* AVUTIL_SOFTFLOAT_H */ |