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comparison: media/libopus/silk/Inlines.h
media/libopus/silk/Inlines.h
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| 1 /*********************************************************************** | |
| 2 Copyright (c) 2006-2011, Skype Limited. All rights reserved. | |
| 3 Redistribution and use in source and binary forms, with or without | |
| 4 modification, are permitted provided that the following conditions | |
| 5 are met: | |
| 6 - Redistributions of source code must retain the above copyright notice, | |
| 7 this list of conditions and the following disclaimer. | |
| 8 - Redistributions in binary form must reproduce the above copyright | |
| 9 notice, this list of conditions and the following disclaimer in the | |
| 10 documentation and/or other materials provided with the distribution. | |
| 11 - Neither the name of Internet Society, IETF or IETF Trust, nor the | |
| 12 names of specific contributors, may be used to endorse or promote | |
| 13 products derived from this software without specific prior written | |
| 14 permission. | |
| 15 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" | |
| 16 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
| 17 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
| 18 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE | |
| 19 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR | |
| 20 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF | |
| 21 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS | |
| 22 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN | |
| 23 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | |
| 24 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | |
| 25 POSSIBILITY OF SUCH DAMAGE. | |
| 26 ***********************************************************************/ | |
| 27 | |
| 28 /*! \file silk_Inlines.h | |
| 29 * \brief silk_Inlines.h defines OPUS_INLINE signal processing functions. | |
| 30 */ | |
| 31 | |
| 32 #ifndef SILK_FIX_INLINES_H | |
| 33 #define SILK_FIX_INLINES_H | |
| 34 | |
| 35 #ifdef __cplusplus | |
| 36 extern "C" | |
| 37 { | |
| 38 #endif | |
| 39 | |
| 40 /* count leading zeros of opus_int64 */ | |
| 41 static OPUS_INLINE opus_int32 silk_CLZ64( opus_int64 in ) | |
| 42 { | |
| 43 opus_int32 in_upper; | |
| 44 | |
| 45 in_upper = (opus_int32)silk_RSHIFT64(in, 32); | |
| 46 if (in_upper == 0) { | |
| 47 /* Search in the lower 32 bits */ | |
| 48 return 32 + silk_CLZ32( (opus_int32) in ); | |
| 49 } else { | |
| 50 /* Search in the upper 32 bits */ | |
| 51 return silk_CLZ32( in_upper ); | |
| 52 } | |
| 53 } | |
| 54 | |
| 55 /* get number of leading zeros and fractional part (the bits right after the leading one */ | |
| 56 static OPUS_INLINE void silk_CLZ_FRAC( | |
| 57 opus_int32 in, /* I input */ | |
| 58 opus_int32 *lz, /* O number of leading zeros */ | |
| 59 opus_int32 *frac_Q7 /* O the 7 bits right after the leading one */ | |
| 60 ) | |
| 61 { | |
| 62 opus_int32 lzeros = silk_CLZ32(in); | |
| 63 | |
| 64 * lz = lzeros; | |
| 65 * frac_Q7 = silk_ROR32(in, 24 - lzeros) & 0x7f; | |
| 66 } | |
| 67 | |
| 68 /* Approximation of square root */ | |
| 69 /* Accuracy: < +/- 10% for output values > 15 */ | |
| 70 /* < +/- 2.5% for output values > 120 */ | |
| 71 static OPUS_INLINE opus_int32 silk_SQRT_APPROX( opus_int32 x ) | |
| 72 { | |
| 73 opus_int32 y, lz, frac_Q7; | |
| 74 | |
| 75 if( x <= 0 ) { | |
| 76 return 0; | |
| 77 } | |
| 78 | |
| 79 silk_CLZ_FRAC(x, &lz, &frac_Q7); | |
| 80 | |
| 81 if( lz & 1 ) { | |
| 82 y = 32768; | |
| 83 } else { | |
| 84 y = 46214; /* 46214 = sqrt(2) * 32768 */ | |
| 85 } | |
| 86 | |
| 87 /* get scaling right */ | |
| 88 y >>= silk_RSHIFT(lz, 1); | |
| 89 | |
| 90 /* increment using fractional part of input */ | |
| 91 y = silk_SMLAWB(y, y, silk_SMULBB(213, frac_Q7)); | |
| 92 | |
| 93 return y; | |
| 94 } | |
| 95 | |
| 96 /* Divide two int32 values and return result as int32 in a given Q-domain */ | |
| 97 static OPUS_INLINE opus_int32 silk_DIV32_varQ( /* O returns a good approximation of "(a32 << Qres) / b32" */ | |
| 98 const opus_int32 a32, /* I numerator (Q0) */ | |
| 99 const opus_int32 b32, /* I denominator (Q0) */ | |
| 100 const opus_int Qres /* I Q-domain of result (>= 0) */ | |
| 101 ) | |
| 102 { | |
| 103 opus_int a_headrm, b_headrm, lshift; | |
| 104 opus_int32 b32_inv, a32_nrm, b32_nrm, result; | |
| 105 | |
| 106 silk_assert( b32 != 0 ); | |
| 107 silk_assert( Qres >= 0 ); | |
| 108 | |
| 109 /* Compute number of bits head room and normalize inputs */ | |
| 110 a_headrm = silk_CLZ32( silk_abs(a32) ) - 1; | |
| 111 a32_nrm = silk_LSHIFT(a32, a_headrm); /* Q: a_headrm */ | |
| 112 b_headrm = silk_CLZ32( silk_abs(b32) ) - 1; | |
| 113 b32_nrm = silk_LSHIFT(b32, b_headrm); /* Q: b_headrm */ | |
| 114 | |
| 115 /* Inverse of b32, with 14 bits of precision */ | |
| 116 b32_inv = silk_DIV32_16( silk_int32_MAX >> 2, silk_RSHIFT(b32_nrm, 16) ); /* Q: 29 + 16 - b_headrm */ | |
| 117 | |
| 118 /* First approximation */ | |
| 119 result = silk_SMULWB(a32_nrm, b32_inv); /* Q: 29 + a_headrm - b_headrm */ | |
| 120 | |
| 121 /* Compute residual by subtracting product of denominator and first approximation */ | |
| 122 /* It's OK to overflow because the final value of a32_nrm should always be small */ | |
| 123 a32_nrm = silk_SUB32_ovflw(a32_nrm, silk_LSHIFT_ovflw( silk_SMMUL(b32_nrm, result), 3 )); /* Q: a_headrm */ | |
| 124 | |
| 125 /* Refinement */ | |
| 126 result = silk_SMLAWB(result, a32_nrm, b32_inv); /* Q: 29 + a_headrm - b_headrm */ | |
| 127 | |
| 128 /* Convert to Qres domain */ | |
| 129 lshift = 29 + a_headrm - b_headrm - Qres; | |
| 130 if( lshift < 0 ) { | |
| 131 return silk_LSHIFT_SAT32(result, -lshift); | |
| 132 } else { | |
| 133 if( lshift < 32){ | |
| 134 return silk_RSHIFT(result, lshift); | |
| 135 } else { | |
| 136 /* Avoid undefined result */ | |
| 137 return 0; | |
| 138 } | |
| 139 } | |
| 140 } | |
| 141 | |
| 142 /* Invert int32 value and return result as int32 in a given Q-domain */ | |
| 143 static OPUS_INLINE opus_int32 silk_INVERSE32_varQ( /* O returns a good approximation of "(1 << Qres) / b32" */ | |
| 144 const opus_int32 b32, /* I denominator (Q0) */ | |
| 145 const opus_int Qres /* I Q-domain of result (> 0) */ | |
| 146 ) | |
| 147 { | |
| 148 opus_int b_headrm, lshift; | |
| 149 opus_int32 b32_inv, b32_nrm, err_Q32, result; | |
| 150 | |
| 151 silk_assert( b32 != 0 ); | |
| 152 silk_assert( Qres > 0 ); | |
| 153 | |
| 154 /* Compute number of bits head room and normalize input */ | |
| 155 b_headrm = silk_CLZ32( silk_abs(b32) ) - 1; | |
| 156 b32_nrm = silk_LSHIFT(b32, b_headrm); /* Q: b_headrm */ | |
| 157 | |
| 158 /* Inverse of b32, with 14 bits of precision */ | |
| 159 b32_inv = silk_DIV32_16( silk_int32_MAX >> 2, silk_RSHIFT(b32_nrm, 16) ); /* Q: 29 + 16 - b_headrm */ | |
| 160 | |
| 161 /* First approximation */ | |
| 162 result = silk_LSHIFT(b32_inv, 16); /* Q: 61 - b_headrm */ | |
| 163 | |
| 164 /* Compute residual by subtracting product of denominator and first approximation from one */ | |
| 165 err_Q32 = silk_LSHIFT( ((opus_int32)1<<29) - silk_SMULWB(b32_nrm, b32_inv), 3 ); /* Q32 */ | |
| 166 | |
| 167 /* Refinement */ | |
| 168 result = silk_SMLAWW(result, err_Q32, b32_inv); /* Q: 61 - b_headrm */ | |
| 169 | |
| 170 /* Convert to Qres domain */ | |
| 171 lshift = 61 - b_headrm - Qres; | |
| 172 if( lshift <= 0 ) { | |
| 173 return silk_LSHIFT_SAT32(result, -lshift); | |
| 174 } else { | |
| 175 if( lshift < 32){ | |
| 176 return silk_RSHIFT(result, lshift); | |
| 177 }else{ | |
| 178 /* Avoid undefined result */ | |
| 179 return 0; | |
| 180 } | |
| 181 } | |
| 182 } | |
| 183 | |
| 184 #ifdef __cplusplus | |
| 185 } | |
| 186 #endif | |
| 187 | |
| 188 #endif /* SILK_FIX_INLINES_H */ |
