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Allow wrap-around in silk_LPC_analysis_filter()

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This commit is contained in:
Jean-Marc Valin 2011-10-27 13:51:21 -04:00
parent e6a0be8ee6
commit 4a7027b27e
2 changed files with 13 additions and 8 deletions
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18
silk/LPC_analysis_filter.c
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@ -58,18 +58,20 @@ void silk_LPC_analysis_filter(
in_ptr = &in[ ix - 1 ];
out32_Q12 = silk_SMULBB( in_ptr[ 0 ], B[ 0 ] );
out32_Q12 = silk_SMLABB( out32_Q12, in_ptr[ -1 ], B[ 1 ] );
out32_Q12 = silk_SMLABB( out32_Q12, in_ptr[ -2 ], B[ 2 ] );
out32_Q12 = silk_SMLABB( out32_Q12, in_ptr[ -3 ], B[ 3 ] );
out32_Q12 = silk_SMLABB( out32_Q12, in_ptr[ -4 ], B[ 4 ] );
out32_Q12 = silk_SMLABB( out32_Q12, in_ptr[ -5 ], B[ 5 ] );
/* Allowing wrap around so that two wraps can cancel each other. The rare
cases where the result wraps around can only be triggered by invalid streams*/
out32_Q12 = silk_SMLABB_ovflw( out32_Q12, in_ptr[ -1 ], B[ 1 ] );
out32_Q12 = silk_SMLABB_ovflw( out32_Q12, in_ptr[ -2 ], B[ 2 ] );
out32_Q12 = silk_SMLABB_ovflw( out32_Q12, in_ptr[ -3 ], B[ 3 ] );
out32_Q12 = silk_SMLABB_ovflw( out32_Q12, in_ptr[ -4 ], B[ 4 ] );
out32_Q12 = silk_SMLABB_ovflw( out32_Q12, in_ptr[ -5 ], B[ 5 ] );
for( j = 6; j < d; j += 2 ) {
out32_Q12 = silk_SMLABB( out32_Q12, in_ptr[ -j ], B[ j ] );
out32_Q12 = silk_SMLABB( out32_Q12, in_ptr[ -j - 1 ], B[ j + 1 ] );
out32_Q12 = silk_SMLABB_ovflw( out32_Q12, in_ptr[ -j ], B[ j ] );
out32_Q12 = silk_SMLABB_ovflw( out32_Q12, in_ptr[ -j - 1 ], B[ j + 1 ] );
}
/* Subtract prediction */
out32_Q12 = silk_SUB32( silk_LSHIFT( (opus_int32)in_ptr[ 1 ], 12 ), out32_Q12 );
out32_Q12 = silk_SUB32_ovflw( silk_LSHIFT( (opus_int32)in_ptr[ 1 ], 12 ), out32_Q12 );
/* Scale to Q0 */
out32 = silk_RSHIFT_ROUND( out32_Q12, 12 );

3
silk/SigProc_FIX.h
View file

@ -421,6 +421,9 @@ static inline opus_int32 silk_ROR32( opus_int32 a32, opus_int rot )
(just standard two's complement implementation-specific behaviour) */
#define silk_SUB32_ovflw(a, b) ((opus_int32)((opus_uint32)(a) - (opus_uint32)(b)))
/* a32 + (opus_int32)((opus_int16)(b32)) * (opus_int32)((opus_int16)(c32)) output have to be 32bit int */
#define silk_SMLABB_ovflw(a32, b32, c32) (silk_ADD32_ovflw((a32) , ((opus_int32)((opus_int16)(b32))) * (opus_int32)((opus_int16)(c32))))
/* Multiply-accumulate macros that allow overflow in the addition (ie, no asserts in debug mode)*/
#define silk_MLA_ovflw(a32, b32, c32) silk_ADD32_ovflw((a32), (opus_uint32)(b32) * (opus_uint32)(c32))
#ifndef silk_SMLABB_ovflw