/* * 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 -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};             ///< 0.0static const SoftFloat FLOAT_05         = { 0x20000000,   0};                   ///< 0.5static const SoftFloat FLOAT_1          = { 0x20000000,   1};                   ///< 1.0static const SoftFloat FLOAT_EPSILON    = { 0x29F16B12, -16};                   ///< A small valuestatic const SoftFloat FLOAT_1584893192 = { 0x32B771ED,   1};                   ///< 1.584893192 (10^.2)static const SoftFloat FLOAT_100000     = { 0x30D40000,  17};                   ///< 100000static const SoftFloat FLOAT_0999999    = { 0x3FFFFBCE,   0};                   ///< 0.999999  /** * 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 */