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| |
| /*! \file silk_Inlines.h |
| * \brief silk_Inlines.h defines OPUS_INLINE signal processing functions. |
| */ |
| |
| #ifndef SILK_FIX_INLINES_H |
| #define SILK_FIX_INLINES_H |
| |
| #ifdef __cplusplus |
| extern "C" |
| { |
| #endif |
| |
| /* count leading zeros of opus_int64 */ |
| static OPUS_INLINE opus_int32 silk_CLZ64( opus_int64 in ) |
| { |
| opus_int32 in_upper; |
| |
| in_upper = (opus_int32)silk_RSHIFT64(in, 32); |
| if (in_upper == 0) { |
| /* Search in the lower 32 bits */ |
| return 32 + silk_CLZ32( (opus_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 */ |
| static OPUS_INLINE void silk_CLZ_FRAC( |
| opus_int32 in, /* I input */ |
| opus_int32 *lz, /* O number of leading zeros */ |
| opus_int32 *frac_Q7 /* O the 7 bits right after the leading one */ |
| ) |
| { |
| opus_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 */ |
| static OPUS_INLINE opus_int32 silk_SQRT_APPROX( opus_int32 x ) |
| { |
| opus_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 >>= silk_RSHIFT(lz, 1); |
| |
| /* increment using fractional part of input */ |
| y = silk_SMLAWB(y, y, silk_SMULBB(213, frac_Q7)); |
| |
| return y; |
| } |
| |
| /* Divide two int32 values and return result as int32 in a given Q-domain */ |
| static OPUS_INLINE opus_int32 silk_DIV32_varQ( /* O returns a good approximation of "(a32 << Qres) / b32" */ |
| const opus_int32 a32, /* I numerator (Q0) */ |
| const opus_int32 b32, /* I denominator (Q0) */ |
| const opus_int Qres /* I Q-domain of result (>= 0) */ |
| ) |
| { |
| opus_int a_headrm, b_headrm, lshift; |
| opus_int32 b32_inv, a32_nrm, b32_nrm, result; |
| |
| silk_assert( b32 != 0 ); |
| silk_assert( Qres >= 0 ); |
| |
| /* Compute number of bits head room and normalize inputs */ |
| a_headrm = silk_CLZ32( silk_abs(a32) ) - 1; |
| a32_nrm = silk_LSHIFT(a32, a_headrm); /* Q: a_headrm */ |
| b_headrm = silk_CLZ32( silk_abs(b32) ) - 1; |
| b32_nrm = silk_LSHIFT(b32, b_headrm); /* Q: b_headrm */ |
| |
| /* Inverse of b32, with 14 bits of precision */ |
| b32_inv = silk_DIV32_16( silk_int32_MAX >> 2, silk_RSHIFT(b32_nrm, 16) ); /* Q: 29 + 16 - b_headrm */ |
| |
| /* First approximation */ |
| result = silk_SMULWB(a32_nrm, b32_inv); /* Q: 29 + a_headrm - b_headrm */ |
| |
| /* Compute residual by subtracting product of denominator and first approximation */ |
| /* It's OK to overflow because the final value of a32_nrm should always be small */ |
| a32_nrm = silk_SUB32_ovflw(a32_nrm, silk_LSHIFT_ovflw( silk_SMMUL(b32_nrm, result), 3 )); /* Q: a_headrm */ |
| |
| /* Refinement */ |
| result = silk_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 silk_LSHIFT_SAT32(result, -lshift); |
| } else { |
| if( lshift < 32){ |
| return silk_RSHIFT(result, lshift); |
| } else { |
| /* Avoid undefined result */ |
| return 0; |
| } |
| } |
| } |
| |
| /* Invert int32 value and return result as int32 in a given Q-domain */ |
| static OPUS_INLINE opus_int32 silk_INVERSE32_varQ( /* O returns a good approximation of "(1 << Qres) / b32" */ |
| const opus_int32 b32, /* I denominator (Q0) */ |
| const opus_int Qres /* I Q-domain of result (> 0) */ |
| ) |
| { |
| opus_int b_headrm, lshift; |
| opus_int32 b32_inv, b32_nrm, err_Q32, result; |
| |
| silk_assert( b32 != 0 ); |
| silk_assert( Qres > 0 ); |
| |
| /* Compute number of bits head room and normalize input */ |
| b_headrm = silk_CLZ32( silk_abs(b32) ) - 1; |
| b32_nrm = silk_LSHIFT(b32, b_headrm); /* Q: b_headrm */ |
| |
| /* Inverse of b32, with 14 bits of precision */ |
| b32_inv = silk_DIV32_16( silk_int32_MAX >> 2, silk_RSHIFT(b32_nrm, 16) ); /* Q: 29 + 16 - b_headrm */ |
| |
| /* First approximation */ |
| result = silk_LSHIFT(b32_inv, 16); /* Q: 61 - b_headrm */ |
| |
| /* Compute residual by subtracting product of denominator and first approximation from one */ |
| err_Q32 = silk_LSHIFT( ((opus_int32)1<<29) - silk_SMULWB(b32_nrm, b32_inv), 3 ); /* Q32 */ |
| |
| /* Refinement */ |
| result = silk_SMLAWW(result, err_Q32, b32_inv); /* Q: 61 - b_headrm */ |
| |
| /* Convert to Qres domain */ |
| lshift = 61 - b_headrm - Qres; |
| if( lshift <= 0 ) { |
| return silk_LSHIFT_SAT32(result, -lshift); |
| } else { |
| if( lshift < 32){ |
| return silk_RSHIFT(result, lshift); |
| }else{ |
| /* Avoid undefined result */ |
| return 0; |
| } |
| } |
| } |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| |
| #endif /* SILK_FIX_INLINES_H */ |
