diff options
Diffstat (limited to 'libavutil/softfloat.h')
-rw-r--r-- | libavutil/softfloat.h | 241 |
1 files changed, 241 insertions, 0 deletions
diff --git a/libavutil/softfloat.h b/libavutil/softfloat.h new file mode 100644 index 0000000000..00ff4a1db1 --- /dev/null +++ b/libavutil/softfloat.h @@ -0,0 +1,241 @@ +/* + * 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 const SoftFloat FLOAT_0 = { 0, 0}; +static const SoftFloat FLOAT_05 = { 0x20000000, 0}; +static const SoftFloat FLOAT_1 = { 0x20000000, 1}; +static const SoftFloat FLOAT_EPSILON = { 0x29F16B12, -16}; +static const SoftFloat FLOAT_1584893192 = { 0x32B771ED, 1}; +static const SoftFloat FLOAT_100000 = { 0x30D40000, 17}; +static const SoftFloat FLOAT_0999999 = { 0x3FFFFBCE, 0}; + +static inline av_const double av_sf2double(SoftFloat v) { + v.exp -= ONE_BITS +1; + if(v.exp > 0) return (double)v.mant * (double)(1 << v.exp); + else return (double)v.mant / (double)(1 << (-v.exp)); +} + +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 inline 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. + */ +static av_unused void av_sincos_sf(int a, int *s, int *c) +{ + int idx, sign; + int sv, cv; + int st, ct; + + idx = a >> 26; + sign = (idx << 27) >> 31; + cv = av_costbl_1_sf[idx & 0xf]; + cv = (cv ^ sign) - sign; + + idx -= 8; + sign = (idx << 27) >> 31; + sv = av_costbl_1_sf[idx & 0xf]; + sv = (sv ^ sign) - sign; + + idx = a >> 21; + ct = av_costbl_2_sf[idx & 0x1f]; + st = av_sintbl_2_sf[idx & 0x1f]; + + idx = (int)(((int64_t)cv * ct - (int64_t)sv * st + 0x20000000) >> 30); + + sv = (int)(((int64_t)cv * st + (int64_t)sv * ct + 0x20000000) >> 30); + + cv = idx; + + idx = a >> 16; + ct = av_costbl_3_sf[idx & 0x1f]; + st = av_sintbl_3_sf[idx & 0x1f]; + + idx = (int)(((int64_t)cv * ct - (int64_t)sv * st + 0x20000000) >> 30); + + sv = (int)(((int64_t)cv * st + (int64_t)sv * ct + 0x20000000) >> 30); + cv = idx; + + idx = a >> 11; + + ct = (int)(((int64_t)av_costbl_4_sf[idx & 0x1f] * (0x800 - (a & 0x7ff)) + + (int64_t)av_costbl_4_sf[(idx & 0x1f)+1]*(a & 0x7ff) + + 0x400) >> 11); + st = (int)(((int64_t)av_sintbl_4_sf[idx & 0x1f] * (0x800 - (a & 0x7ff)) + + (int64_t)av_sintbl_4_sf[(idx & 0x1f) + 1] * (a & 0x7ff) + + 0x400) >> 11); + + *c = (int)(((int64_t)cv * ct + (int64_t)sv * st + 0x20000000) >> 30); + + *s = (int)(((int64_t)cv * st + (int64_t)sv * ct + 0x20000000) >> 30); +} + +#endif /* AVUTIL_SOFTFLOAT_H */ |