372 lines
10 KiB
C
Executable File
372 lines
10 KiB
C
Executable File
/* Copyright (C) 2002-2008 Jean-Marc Valin */
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/**
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@file mathops.h
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@brief Various math functions
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*/
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/*
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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- Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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- Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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- Neither the name of the Xiph.org Foundation nor the names of its
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contributors may be used to endorse or promote products derived from
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this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR
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CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef MATHOPS_H
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#define MATHOPS_H
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#include "arch.h"
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#include "entcode.h"
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#include "os_support.h"
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#ifndef OVERRIDE_CELT_ILOG2
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/** Integer log in base2. Undefined for zero and negative numbers */
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static __inline celt_int16_t celt_ilog2(celt_word32_t x)
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{
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celt_assert2(x>0, "celt_ilog2() only defined for strictly positive numbers");
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return EC_ILOG(x)-1;
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}
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#endif
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#ifndef OVERRIDE_FIND_MAX16
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static __inline int find_max16(celt_word16_t *x, int len)
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{
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celt_word16_t max_corr=-VERY_LARGE16;
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int i, id = 0;
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for (i=0;i<len;i++)
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{
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if (x[i] > max_corr)
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{
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id = i;
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max_corr = x[i];
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}
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}
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return id;
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}
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#endif
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#ifndef OVERRIDE_FIND_MAX32
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static __inline int find_max32(celt_word32_t *x, int len)
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{
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celt_word32_t max_corr=-VERY_LARGE32;
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int i, id = 0;
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for (i=0;i<len;i++)
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{
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if (x[i] > max_corr)
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{
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id = i;
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max_corr = x[i];
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}
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}
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return id;
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}
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#endif
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#define FRAC_MUL16(a,b) ((16384+((celt_int32_t)(celt_int16_t)(a)*(celt_int16_t)(b)))>>15)
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static __inline celt_int16_t bitexact_cos(celt_int16_t x)
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{
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celt_int32_t tmp;
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celt_int16_t x2;
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tmp = (4096+((celt_int32_t)(x)*(x)))>>13;
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if (tmp > 32767)
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tmp = 32767;
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x2 = tmp;
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x2 = (32767-x2) + FRAC_MUL16(x2, (-7651 + FRAC_MUL16(x2, (8277 + FRAC_MUL16(-626, x2)))));
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if (x2 > 32766)
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x2 = 32766;
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return 1+x2;
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}
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#ifndef FIXED_POINT
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#define celt_sqrt(x) ((float)sqrt(x))
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#define celt_psqrt(x) ((float)sqrt(x))
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#define celt_rsqrt(x) (1.f/celt_sqrt(x))
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#define celt_acos acos
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#define celt_exp exp
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#define celt_cos_norm(x) (cos((.5f*M_PI)*(x)))
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#define celt_atan atan
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#define celt_rcp(x) (1.f/(x))
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#define celt_div(a,b) ((a)/(b))
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#ifdef FLOAT_APPROX
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/* Note: This assumes radix-2 floating point with the exponent at bits 23..30 and an offset of 127
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denorm, +/- inf and NaN are *not* handled */
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/** Base-2 log approximation (log2(x)). */
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static inline float celt_log2(float x)
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{
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int integer;
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float frac;
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union {
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float f;
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celt_uint32_t i;
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} in;
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in.f = x;
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integer = (in.i>>23)-127;
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in.i -= integer<<23;
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frac = in.f - 1.5;
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/* -0.41446 0.96093 -0.33981 0.15600 */
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frac = -0.41446 + frac*(0.96093 + frac*(-0.33981 + frac*0.15600));
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return 1+integer+frac;
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}
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/** Base-2 exponential approximation (2^x). */
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static inline float celt_exp2(float x)
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{
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int integer;
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float frac;
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union {
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float f;
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celt_uint32_t i;
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} res;
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integer = floor(x);
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if (integer < -50)
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return 0;
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frac = x-integer;
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/* K0 = 1, K1 = log(2), K2 = 3-4*log(2), K3 = 3*log(2) - 2 */
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res.f = 1.f + frac * (0.696147f + frac * (0.224411f + 0.079442f*frac));
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res.i = (res.i + (integer<<23)) & 0x7fffffff;
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return res.f;
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}
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#else
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#define celt_log2(x) (1.442695040888963387*log(x))
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#define celt_exp2(x) (exp(0.6931471805599453094*(x)))
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#endif
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#endif
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#ifdef FIXED_POINT
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#include "os_support.h"
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#ifndef OVERRIDE_CELT_MAXABS16
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static inline celt_word16_t celt_maxabs16(celt_word16_t *x, int len)
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{
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int i;
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celt_word16_t maxval = 0;
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for (i=0;i<len;i++)
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maxval = MAX16(maxval, ABS16(x[i]));
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return maxval;
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}
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#endif
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/** Integer log in base2. Defined for zero, but not for negative numbers */
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static inline celt_int16_t celt_zlog2(celt_word32_t x)
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{
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return x <= 0 ? 0 : celt_ilog2(x);
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}
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/** Reciprocal sqrt approximation (Q30 input, Q0 output or equivalent) */
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static inline celt_word32_t celt_rsqrt(celt_word32_t x)
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{
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int k;
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celt_word16_t n;
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celt_word32_t rt;
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const celt_word16_t C[5] = {23126, -11496, 9812, -9097, 4100};
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k = celt_ilog2(x)>>1;
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x = VSHR32(x, (k-7)<<1);
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/* Range of n is [-16384,32767] */
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n = x-32768;
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rt = ADD16(C[0], MULT16_16_Q15(n, ADD16(C[1], MULT16_16_Q15(n, ADD16(C[2],
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MULT16_16_Q15(n, ADD16(C[3], MULT16_16_Q15(n, (C[4])))))))));
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rt = VSHR32(rt,k);
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return rt;
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}
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/** Sqrt approximation (QX input, QX/2 output) */
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static inline celt_word32_t celt_sqrt(celt_word32_t x)
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{
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int k;
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celt_word16_t n;
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celt_word32_t rt;
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const celt_word16_t C[5] = {23174, 11584, -3011, 1570, -557};
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if (x==0)
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return 0;
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k = (celt_ilog2(x)>>1)-7;
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x = VSHR32(x, (k<<1));
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n = x-32768;
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rt = ADD16(C[0], MULT16_16_Q15(n, ADD16(C[1], MULT16_16_Q15(n, ADD16(C[2],
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MULT16_16_Q15(n, ADD16(C[3], MULT16_16_Q15(n, (C[4])))))))));
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rt = VSHR32(rt,7-k);
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return rt;
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}
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/** Sqrt approximation (QX input, QX/2 output) that assumes that the input is
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strictly positive */
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static inline celt_word32_t celt_psqrt(celt_word32_t x)
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{
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int k;
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celt_word16_t n;
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celt_word32_t rt;
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const celt_word16_t C[5] = {23174, 11584, -3011, 1570, -557};
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k = (celt_ilog2(x)>>1)-7;
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x = VSHR32(x, (k<<1));
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n = x-32768;
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rt = ADD16(C[0], MULT16_16_Q15(n, ADD16(C[1], MULT16_16_Q15(n, ADD16(C[2],
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MULT16_16_Q15(n, ADD16(C[3], MULT16_16_Q15(n, (C[4])))))))));
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rt = VSHR32(rt,7-k);
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return rt;
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}
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#define L1 32767
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#define L2 -7651
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#define L3 8277
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#define L4 -626
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static inline celt_word16_t _celt_cos_pi_2(celt_word16_t x)
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{
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celt_word16_t x2;
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x2 = MULT16_16_P15(x,x);
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return ADD16(1,MIN16(32766,ADD32(SUB16(L1,x2), MULT16_16_P15(x2, ADD32(L2, MULT16_16_P15(x2, ADD32(L3, MULT16_16_P15(L4, x2
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))))))));
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}
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#undef L1
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#undef L2
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#undef L3
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#undef L4
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static inline celt_word16_t celt_cos_norm(celt_word32_t x)
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{
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x = x&0x0001ffff;
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if (x>SHL32(EXTEND32(1), 16))
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x = SUB32(SHL32(EXTEND32(1), 17),x);
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if (x&0x00007fff)
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{
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if (x<SHL32(EXTEND32(1), 15))
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{
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return _celt_cos_pi_2(EXTRACT16(x));
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} else {
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return NEG32(_celt_cos_pi_2(EXTRACT16(65536-x)));
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}
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} else {
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if (x&0x0000ffff)
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return 0;
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else if (x&0x0001ffff)
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return -32767;
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else
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return 32767;
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}
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}
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static inline celt_word16_t celt_log2(celt_word32_t x)
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{
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int i;
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celt_word16_t n, frac;
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/*-0.41446 0.96093 -0.33981 0.15600 */
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const celt_word16_t C[4] = {-6791, 7872, -1392, 319};
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if (x==0)
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return -32767;
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i = celt_ilog2(x);
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n = VSHR32(x,i-15)-32768-16384;
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frac = ADD16(C[0], MULT16_16_Q14(n, ADD16(C[1], MULT16_16_Q14(n, ADD16(C[2], MULT16_16_Q14(n, (C[3])))))));
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return SHL16(i-13,8)+SHR16(frac,14-8);
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}
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/*
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K0 = 1
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K1 = log(2)
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K2 = 3-4*log(2)
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K3 = 3*log(2) - 2
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*/
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#define D0 16384
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#define D1 11356
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#define D2 3726
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#define D3 1301
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/** Base-2 exponential approximation (2^x). (Q11 input, Q16 output) */
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static inline celt_word32_t celt_exp2(celt_word16_t x)
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{
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int integer;
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celt_word16_t frac;
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integer = SHR16(x,11);
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if (integer>14)
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return 0x7f000000;
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else if (integer < -15)
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return 0;
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frac = SHL16(x-SHL16(integer,11),3);
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frac = ADD16(D0, MULT16_16_Q14(frac, ADD16(D1, MULT16_16_Q14(frac, ADD16(D2 , MULT16_16_Q14(D3,frac))))));
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return VSHR32(EXTEND32(frac), -integer-2);
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}
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/** Reciprocal approximation (Q15 input, Q16 output) */
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static inline celt_word32_t celt_rcp(celt_word32_t x)
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{
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int i;
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celt_word16_t n, frac;
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const celt_word16_t C[5] = {21848, -7251, 2403, -934, 327};
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celt_assert2(x>0, "celt_rcp() only defined for positive values");
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i = celt_ilog2(x);
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n = VSHR32(x,i-16)-SHL32(EXTEND32(3),15);
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frac = ADD16(C[0], MULT16_16_Q15(n, ADD16(C[1], MULT16_16_Q15(n, ADD16(C[2],
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MULT16_16_Q15(n, ADD16(C[3], MULT16_16_Q15(n, (C[4])))))))));
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return VSHR32(EXTEND32(frac),i-16);
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}
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#define celt_div(a,b) MULT32_32_Q31((celt_word32_t)(a),celt_rcp(b))
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#define M1 32767
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#define M2 -21
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#define M3 -11943
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#define M4 4936
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static inline celt_word16_t celt_atan01(celt_word16_t x)
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{
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return MULT16_16_P15(x, ADD32(M1, MULT16_16_P15(x, ADD32(M2, MULT16_16_P15(x, ADD32(M3, MULT16_16_P15(M4, x)))))));
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}
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#undef M1
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#undef M2
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#undef M3
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#undef M4
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static inline celt_word16_t celt_atan2p(celt_word16_t y, celt_word16_t x)
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{
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if (y < x)
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{
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celt_word32_t arg;
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arg = celt_div(SHL32(EXTEND32(y),15),x);
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if (arg >= 32767)
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arg = 32767;
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return SHR16(celt_atan01(EXTRACT16(arg)),1);
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} else {
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celt_word32_t arg;
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arg = celt_div(SHL32(EXTEND32(x),15),y);
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if (arg >= 32767)
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arg = 32767;
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return 25736-SHR16(celt_atan01(EXTRACT16(arg)),1);
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}
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}
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#endif /* FIXED_POINT */
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#endif /* MATHOPS_H */
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