/* * Copyright (c) 2006 Michael Niedermayer * * 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 #include "common.h" #include "avassert.h" #include "softfloat_tables.h" #define MIN_EXP -149 #define MAX_EXP 126 #define ONE_BITS 29 typedef struct SoftFloat{ int32_t mant; int32_t exp; }SoftFloat; static const SoftFloat FLOAT_0 = { 0, MIN_EXP}; ///< 0.0 static const SoftFloat FLOAT_05 = { 0x20000000, 0}; ///< 0.5 static const SoftFloat FLOAT_1 = { 0x20000000, 1}; ///< 1.0 static const SoftFloat FLOAT_EPSILON = { 0x29F16B12, -16}; ///< A small value static const SoftFloat FLOAT_1584893192 = { 0x32B771ED, 1}; ///< 1.584893192 (10^.2) static const SoftFloat FLOAT_100000 = { 0x30D40000, 17}; ///< 100000 static const SoftFloat FLOAT_0999999 = { 0x3FFFFBCE, 0}; ///< 0.999999 static const SoftFloat FLOAT_MIN = { 0x20000000, MIN_EXP}; /** * Convert a SoftFloat to a double precision float. */ static inline av_const double av_sf2double(SoftFloat v) { v.exp -= ONE_BITS +1; return ldexp(v.mant, 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); av_assert2(a.exp <= MAX_EXP); 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; a = av_normalize1_sf((SoftFloat){a.mant, a.exp - 1}); if (!a.mant || a.exp < MIN_EXP) return FLOAT_0; return a; } /** * 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){ int64_t temp = (int64_t)a.mant * (1<<(ONE_BITS+1)); temp /= b.mant; a.exp -= b.exp; a.mant = temp; while (a.mant != temp) { temp /= 2; a.exp--; a.mant = temp; } a = av_normalize1_sf(a); if (!a.mant || a.exp < MIN_EXP) return FLOAT_0; return a; } /** * Compares two SoftFloats. * @returns < 0 if the first is less * > 0 if the first is greater * 0 if they are equal */ static inline av_const int av_cmp_sf(SoftFloat a, SoftFloat b){ int t= a.exp - b.exp; if (t <-31) return - b.mant ; else if (t < 0) return (a.mant >> (-t)) - b.mant ; else if (t < 32) return a.mant - (b.mant >> t); else return a.mant ; } /** * Compares two SoftFloats. * @returns 1 if a is greater than b, 0 otherwise */ static inline av_const int av_gt_sf(SoftFloat a, SoftFloat b) { int t= a.exp - b.exp; if (t <-31) return 0 > b.mant ; else if (t < 0) return (a.mant >> (-t)) > b.mant ; else if (t < 32) return a.mant > (b.mant >> t); else return a.mant > 0 ; } /** * @returns the sum of 2 SoftFloats. */ 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; } /** * @returns the difference of 2 SoftFloats. */ 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. * This converts a fixed point value v with frac_bits fractional bits to a * SoftFloat. * @returns a SoftFloat with value v * 2^-frac_bits */ static inline av_const SoftFloat av_int2sf(int v, int frac_bits){ int exp_offset = 0; if(v <= INT_MIN + 1){ exp_offset = 1; v>>=1; } return av_normalize_sf(av_normalize1_sf((SoftFloat){v, ONE_BITS + 1 - frac_bits + exp_offset})); } /** * Converts a SoftFloat to an integer. * 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 = MIN_EXP; else if (val.mant < 0) abort(); 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 = (int32_t)((unsigned)idx << 27) >> 31; cv = av_costbl_1_sf[idx & 0xf]; cv = (cv ^ sign) - sign; idx -= 8; sign = (int32_t)((unsigned)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 */