ref: 8ff61171250502a6059995c05902caf06ab07acf
dir: /silk/silk_Inlines.h/
/*********************************************************************** Copyright (c) 2006-2011, Skype Limited. All rights reserved. Redistribution and use in source and binary forms, with or without modification, (subject to the limitations in the disclaimer below) are permitted provided that the following conditions are met: - Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. - Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. - Neither the name of Skype Limited, nor the names of specific contributors, may be used to endorse or promote products derived from this software without specific prior written permission. NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE GRANTED BY THIS LICENSE. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. ***********************************************************************/ /*! \file silk_Inlines.h * \brief silk_Inlines.h defines inline signal processing functions. */ #ifndef _SILK_FIX_INLINES_H_ #define _SILK_FIX_INLINES_H_ #ifdef __cplusplus extern "C" { #endif /* count leading zeros of SKP_int64 */ SKP_INLINE SKP_int32 silk_CLZ64(SKP_int64 in) { SKP_int32 in_upper; in_upper = (SKP_int32)SKP_RSHIFT64(in, 32); if (in_upper == 0) { /* Search in the lower 32 bits */ return 32 + silk_CLZ32( (SKP_int32) in ); } else { /* Search in the upper 32 bits */ return silk_CLZ32( in_upper ); } } /* get number of leading zeros and fractional part (the bits right after the leading one */ SKP_INLINE void silk_CLZ_FRAC(SKP_int32 in, /* I: input */ SKP_int32 *lz, /* O: number of leading zeros */ SKP_int32 *frac_Q7) /* O: the 7 bits right after the leading one */ { SKP_int32 lzeros = silk_CLZ32(in); * lz = lzeros; * frac_Q7 = silk_ROR32(in, 24 - lzeros) & 0x7f; } /* Approximation of square root */ /* Accuracy: < +/- 10% for output values > 15 */ /* < +/- 2.5% for output values > 120 */ SKP_INLINE SKP_int32 silk_SQRT_APPROX(SKP_int32 x) { SKP_int32 y, lz, frac_Q7; if( x <= 0 ) { return 0; } silk_CLZ_FRAC(x, &lz, &frac_Q7); if( lz & 1 ) { y = 32768; } else { y = 46214; /* 46214 = sqrt(2) * 32768 */ } /* get scaling right */ y >>= SKP_RSHIFT(lz, 1); /* increment using fractional part of input */ y = SKP_SMLAWB(y, y, SKP_SMULBB(213, frac_Q7)); return y; } /* Divide two int32 values and return result as int32 in a given Q-domain */ SKP_INLINE SKP_int32 silk_DIV32_varQ( /* O returns a good approximation of "(a32 << Qres) / b32" */ const SKP_int32 a32, /* I numerator (Q0) */ const SKP_int32 b32, /* I denominator (Q0) */ const SKP_int Qres /* I Q-domain of result (>= 0) */ ) { SKP_int a_headrm, b_headrm, lshift; SKP_int32 b32_inv, a32_nrm, b32_nrm, result; SKP_assert( b32 != 0 ); SKP_assert( Qres >= 0 ); /* Compute number of bits head room and normalize inputs */ a_headrm = silk_CLZ32( SKP_abs(a32) ) - 1; a32_nrm = SKP_LSHIFT(a32, a_headrm); /* Q: a_headrm */ b_headrm = silk_CLZ32( SKP_abs(b32) ) - 1; b32_nrm = SKP_LSHIFT(b32, b_headrm); /* Q: b_headrm */ /* Inverse of b32, with 14 bits of precision */ b32_inv = SKP_DIV32_16( SKP_int32_MAX >> 2, SKP_RSHIFT(b32_nrm, 16) ); /* Q: 29 + 16 - b_headrm */ /* First approximation */ result = SKP_SMULWB(a32_nrm, b32_inv); /* Q: 29 + a_headrm - b_headrm */ /* Compute residual by subtracting product of denominator and first approximation */ a32_nrm -= SKP_LSHIFT_ovflw( SKP_SMMUL(b32_nrm, result), 3 ); /* Q: a_headrm */ /* Refinement */ result = SKP_SMLAWB(result, a32_nrm, b32_inv); /* Q: 29 + a_headrm - b_headrm */ /* Convert to Qres domain */ lshift = 29 + a_headrm - b_headrm - Qres; if( lshift < 0 ) { return SKP_LSHIFT_SAT32(result, -lshift); } else { if( lshift < 32){ return SKP_RSHIFT(result, lshift); } else { /* Avoid undefined result */ return 0; } } } /* Invert int32 value and return result as int32 in a given Q-domain */ SKP_INLINE SKP_int32 silk_INVERSE32_varQ( /* O returns a good approximation of "(1 << Qres) / b32" */ const SKP_int32 b32, /* I denominator (Q0) */ const SKP_int Qres /* I Q-domain of result (> 0) */ ) { SKP_int b_headrm, lshift; SKP_int32 b32_inv, b32_nrm, err_Q32, result; SKP_assert( b32 != 0 ); SKP_assert( Qres > 0 ); /* Compute number of bits head room and normalize input */ b_headrm = silk_CLZ32( SKP_abs(b32) ) - 1; b32_nrm = SKP_LSHIFT(b32, b_headrm); /* Q: b_headrm */ /* Inverse of b32, with 14 bits of precision */ b32_inv = SKP_DIV32_16( SKP_int32_MAX >> 2, SKP_RSHIFT(b32_nrm, 16) ); /* Q: 29 + 16 - b_headrm */ /* First approximation */ result = SKP_LSHIFT(b32_inv, 16); /* Q: 61 - b_headrm */ /* Compute residual by subtracting product of denominator and first approximation from one */ err_Q32 = SKP_LSHIFT_ovflw( -SKP_SMULWB(b32_nrm, b32_inv), 3 ); /* Q32 */ /* Refinement */ result = SKP_SMLAWW(result, err_Q32, b32_inv); /* Q: 61 - b_headrm */ /* Convert to Qres domain */ lshift = 61 - b_headrm - Qres; if( lshift <= 0 ) { return SKP_LSHIFT_SAT32(result, -lshift); } else { if( lshift < 32){ return SKP_RSHIFT(result, lshift); }else{ /* Avoid undefined result */ return 0; } } } #ifdef __cplusplus } #endif #endif //_SILK_FIX_INLINES_H_