279 lines
10 KiB
C
Executable File
279 lines
10 KiB
C
Executable File
/***********************************************************************
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Copyright (c) 2006-2012, Skype Limited. All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, (subject to the limitations in the disclaimer below)
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are permitted provided that the following conditions are met:
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- Redistributions of source code must retain the above copyright notice,
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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 Skype Limited, nor the names of specific
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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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NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE GRANTED
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BY THIS LICENSE. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
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CONTRIBUTORS ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
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BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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***********************************************************************/
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/*! \file SKP_Silk_Inlines.h
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* \brief SigProcFix_Inlines.h defines inline signal processing functions.
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*/
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#ifndef _SKP_SILK_FIX_INLINES_H_
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#define _SKP_SILK_FIX_INLINES_H_
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#include <assert.h>
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#ifdef __cplusplus
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extern "C"
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{
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#endif
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/* count leading zeros of SKP_int64 */
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SKP_INLINE SKP_int32 SKP_Silk_CLZ64(SKP_int64 in)
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{
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SKP_int32 in_upper;
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in_upper = (SKP_int32)SKP_RSHIFT64(in, 32);
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if (in_upper == 0) {
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/* Search in the lower 32 bits */
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return 32 + SKP_Silk_CLZ32( (SKP_int32) in );
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} else {
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/* Search in the upper 32 bits */
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return SKP_Silk_CLZ32( in_upper );
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}
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}
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/* get number of leading zeros and fractional part (the bits right after the leading one */
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SKP_INLINE void SKP_Silk_CLZ_FRAC(SKP_int32 in, /* I: input */
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SKP_int32 *lz, /* O: number of leading zeros */
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SKP_int32 *frac_Q7) /* O: the 7 bits right after the leading one */
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{
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SKP_int32 lzeros = SKP_Silk_CLZ32(in);
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* lz = lzeros;
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* frac_Q7 = SKP_ROR32(in, 24 - lzeros) & 0x7f;
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}
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/* Approximation of square root */
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/* Accuracy: < +/- 10% for output values > 15 */
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/* < +/- 2.5% for output values > 120 */
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SKP_INLINE SKP_int32 SKP_Silk_SQRT_APPROX(SKP_int32 x)
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{
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SKP_int32 y, lz, frac_Q7;
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if( x <= 0 ) {
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return 0;
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}
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SKP_Silk_CLZ_FRAC(x, &lz, &frac_Q7);
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if( lz & 1 ) {
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y = 32768;
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} else {
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y = 46214; /* 46214 = sqrt(2) * 32768 */
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}
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/* get scaling right */
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y >>= SKP_RSHIFT(lz, 1);
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/* increment using fractional part of input */
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y = SKP_SMLAWB(y, y, SKP_SMULBB(213, frac_Q7));
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return y;
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}
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/* returns the number of left shifts before overflow for a 16 bit number (ITU definition with norm(0)=0) */
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SKP_INLINE SKP_int32 SKP_Silk_norm16(SKP_int16 a) {
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SKP_int32 a32;
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/* if ((a == 0) || (a == SKP_int16_MIN)) return(0); */
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if ((a << 1) == 0) return(0);
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a32 = a;
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/* if (a32 < 0) a32 = -a32 - 1; */
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a32 ^= SKP_RSHIFT(a32, 31);
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return SKP_Silk_CLZ32(a32) - 17;
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}
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/* returns the number of left shifts before overflow for a 32 bit number (ITU definition with norm(0)=0) */
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SKP_INLINE SKP_int32 SKP_Silk_norm32(SKP_int32 a) {
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/* if ((a == 0) || (a == SKP_int32_MIN)) return(0); */
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if ((a << 1) == 0) return(0);
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/* if (a < 0) a = -a - 1; */
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a ^= SKP_RSHIFT(a, 31);
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return SKP_Silk_CLZ32(a) - 1;
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}
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/* Divide two int32 values and return result as int32 in a given Q-domain */
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SKP_INLINE SKP_int32 SKP_DIV32_varQ( /* O returns a good approximation of "(a32 << Qres) / b32" */
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const SKP_int32 a32, /* I numerator (Q0) */
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const SKP_int32 b32, /* I denominator (Q0) */
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const SKP_int Qres /* I Q-domain of result (>= 0) */
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)
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{
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SKP_int a_headrm, b_headrm, lshift;
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SKP_int32 b32_inv, a32_nrm, b32_nrm, result;
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SKP_assert( b32 != 0 );
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SKP_assert( Qres >= 0 );
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/* Compute number of bits head room and normalize inputs */
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a_headrm = SKP_Silk_CLZ32( SKP_abs(a32) ) - 1;
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a32_nrm = SKP_LSHIFT(a32, a_headrm); /* Q: a_headrm */
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b_headrm = SKP_Silk_CLZ32( SKP_abs(b32) ) - 1;
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b32_nrm = SKP_LSHIFT(b32, b_headrm); /* Q: b_headrm */
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/* Inverse of b32, with 14 bits of precision */
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b32_inv = SKP_DIV32_16( SKP_int32_MAX >> 2, SKP_RSHIFT(b32_nrm, 16) ); /* Q: 29 + 16 - b_headrm */
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/* First approximation */
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result = SKP_SMULWB(a32_nrm, b32_inv); /* Q: 29 + a_headrm - b_headrm */
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/* Compute residual by subtracting product of denominator and first approximation */
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a32_nrm -= SKP_LSHIFT_ovflw( SKP_SMMUL(b32_nrm, result), 3 ); /* Q: a_headrm */
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/* Refinement */
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result = SKP_SMLAWB(result, a32_nrm, b32_inv); /* Q: 29 + a_headrm - b_headrm */
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/* Convert to Qres domain */
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lshift = 29 + a_headrm - b_headrm - Qres;
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if( lshift <= 0 ) {
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return SKP_LSHIFT_SAT32(result, -lshift);
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} else {
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if( lshift < 32){
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return SKP_RSHIFT(result, lshift);
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} else {
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/* Avoid undefined result */
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return 0;
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}
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}
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}
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/* Invert int32 value and return result as int32 in a given Q-domain */
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SKP_INLINE SKP_int32 SKP_INVERSE32_varQ( /* O returns a good approximation of "(1 << Qres) / b32" */
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const SKP_int32 b32, /* I denominator (Q0) */
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const SKP_int Qres /* I Q-domain of result (> 0) */
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)
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{
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SKP_int b_headrm, lshift;
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SKP_int32 b32_inv, b32_nrm, err_Q32, result;
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SKP_assert( b32 != 0 );
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SKP_assert( b32 != SKP_int32_MIN ); /* SKP_int32_MIN is not handled by SKP_abs */
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SKP_assert( Qres > 0 );
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/* Compute number of bits head room and normalize input */
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b_headrm = SKP_Silk_CLZ32( SKP_abs(b32) ) - 1;
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b32_nrm = SKP_LSHIFT(b32, b_headrm); /* Q: b_headrm */
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/* Inverse of b32, with 14 bits of precision */
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b32_inv = SKP_DIV32_16( SKP_int32_MAX >> 2, SKP_RSHIFT(b32_nrm, 16) ); /* Q: 29 + 16 - b_headrm */
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/* First approximation */
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result = SKP_LSHIFT(b32_inv, 16); /* Q: 61 - b_headrm */
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/* Compute residual by subtracting product of denominator and first approximation from one */
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err_Q32 = SKP_LSHIFT_ovflw( -SKP_SMULWB(b32_nrm, b32_inv), 3 ); /* Q32 */
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/* Refinement */
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result = SKP_SMLAWW(result, err_Q32, b32_inv); /* Q: 61 - b_headrm */
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/* Convert to Qres domain */
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lshift = 61 - b_headrm - Qres;
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if( lshift <= 0 ) {
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return SKP_LSHIFT_SAT32(result, -lshift);
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} else {
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if( lshift < 32){
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return SKP_RSHIFT(result, lshift);
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}else{
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/* Avoid undefined result */
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return 0;
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}
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}
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}
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#define SKP_SIN_APPROX_CONST0 (1073735400)
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#define SKP_SIN_APPROX_CONST1 (-82778932)
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#define SKP_SIN_APPROX_CONST2 (1059577)
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#define SKP_SIN_APPROX_CONST3 (-5013)
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/* Sine approximation; an input of 65536 corresponds to 2 * pi */
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/* Uses polynomial expansion of the input to the power 0, 2, 4 and 6 */
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/* The relative error is below 1e-5 */
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SKP_INLINE SKP_int32 SKP_Silk_SIN_APPROX_Q24( /* O returns approximately 2^24 * sin(x * 2 * pi / 65536) */
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SKP_int32 x
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)
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{
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SKP_int y_Q30;
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/* Keep only bottom 16 bits (the function repeats itself with period 65536) */
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x &= 65535;
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/* Split range in four quadrants */
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if( x <= 32768 ) {
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if( x < 16384 ) {
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/* Return cos(pi/2 - x) */
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x = 16384 - x;
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} else {
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/* Return cos(x - pi/2) */
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x -= 16384;
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}
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if( x < 1100 ) {
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/* Special case: high accuracy */
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return SKP_SMLAWB( 1 << 24, SKP_MUL( x, x ), -5053 );
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}
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x = SKP_SMULWB( SKP_LSHIFT( x, 8 ), x ); /* contains x^2 in Q20 */
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y_Q30 = SKP_SMLAWB( SKP_SIN_APPROX_CONST2, x, SKP_SIN_APPROX_CONST3 );
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y_Q30 = SKP_SMLAWW( SKP_SIN_APPROX_CONST1, x, y_Q30 );
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y_Q30 = SKP_SMLAWW( SKP_SIN_APPROX_CONST0 + 66, x, y_Q30 );
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} else {
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if( x < 49152 ) {
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/* Return -cos(3*pi/2 - x) */
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x = 49152 - x;
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} else {
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/* Return -cos(x - 3*pi/2) */
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x -= 49152;
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}
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if( x < 1100 ) {
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/* Special case: high accuracy */
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return SKP_SMLAWB( -1 << 24, SKP_MUL( x, x ), 5053 );
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}
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x = SKP_SMULWB( SKP_LSHIFT( x, 8 ), x ); /* contains x^2 in Q20 */
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y_Q30 = SKP_SMLAWB( -SKP_SIN_APPROX_CONST2, x, -SKP_SIN_APPROX_CONST3 );
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y_Q30 = SKP_SMLAWW( -SKP_SIN_APPROX_CONST1, x, y_Q30 );
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y_Q30 = SKP_SMLAWW( -SKP_SIN_APPROX_CONST0, x, y_Q30 );
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}
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return SKP_RSHIFT_ROUND( y_Q30, 6 );
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}
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/* Cosine approximation; an input of 65536 corresponds to 2 * pi */
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/* The relative error is below 1e-5 */
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SKP_INLINE SKP_int32 SKP_Silk_COS_APPROX_Q24( /* O returns approximately 2^24 * cos(x * 2 * pi / 65536) */
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SKP_int32 x
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)
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{
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return SKP_Silk_SIN_APPROX_Q24( x + 16384 );
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}
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#ifdef __cplusplus
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}
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#endif
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#endif /*_SKP_SILK_FIX_INLINES_H_*/
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