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| author | Jean-Marc Valin <jmvalin@jmvalin.ca> | 2016-07-25 11:05:00 -0400 |
|---|---|---|
| committer | Jean-Marc Valin <jmvalin@jmvalin.ca> | 2016-07-25 11:05:00 -0400 |
| commit | 07ca5cc776a04cfbf2fd6423ca6eb78c49eb50a2 (patch) | |
| tree | 836a4540a9521234675035b4e78188b7b61e72a0 | |
| parent | ee44ff86c6ae55eb5c4b568b3822c9b280514c53 (diff) | |
| download | opus-07ca5cc776a04cfbf2fd6423ca6eb78c49eb50a2.tar.gz | |
Fixes an overflow in limit_warped_coefs()
For large values of maxabs_Q20, silk_MUL( maxabs_Q20, ind + 1 ) could
overflow.
| -rw-r--r-- | silk/fixed/noise_shape_analysis_FIX.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/silk/fixed/noise_shape_analysis_FIX.c b/silk/fixed/noise_shape_analysis_FIX.c index 8911a3e9..5d484582 100644 --- a/silk/fixed/noise_shape_analysis_FIX.c +++ b/silk/fixed/noise_shape_analysis_FIX.c @@ -65,6 +65,7 @@ static OPUS_INLINE void limit_warped_coefs( opus_int i, iter, ind = 0; opus_int32 tmp, maxabs_Q24, chirp_Q16, gain_Q16; opus_int32 nom_Q16, den_Q24; + opus_int32 limit_Q20, maxabs_Q20; /* Convert to monic coefficients */ lambda_Q16 = -lambda_Q16; @@ -78,7 +79,7 @@ static OPUS_INLINE void limit_warped_coefs( for( i = 0; i < order; i++ ) { coefs_Q24[ i ] = silk_SMULWW( gain_Q16, coefs_Q24[ i ] ); } - + limit_Q20 = silk_RSHIFT(limit_Q24, 4); for( iter = 0; iter < 10; iter++ ) { /* Find maximum absolute value */ maxabs_Q24 = -1; @@ -89,7 +90,9 @@ static OPUS_INLINE void limit_warped_coefs( ind = i; } } - if( maxabs_Q24 <= limit_Q24 ) { + /* Use Q20 to avoid any overflow when multiplying by (ind + 1) later. */ + maxabs_Q20 = silk_RSHIFT(maxabs_Q24, 4); + if( maxabs_Q20 <= limit_Q20 ) { /* Coefficients are within range - done */ return; } @@ -105,8 +108,8 @@ static OPUS_INLINE void limit_warped_coefs( /* Apply bandwidth expansion */ chirp_Q16 = SILK_FIX_CONST( 0.99, 16 ) - silk_DIV32_varQ( - silk_SMULWB( maxabs_Q24 - limit_Q24, silk_SMLABB( SILK_FIX_CONST( 0.8, 10 ), SILK_FIX_CONST( 0.1, 10 ), iter ) ), - silk_MUL( maxabs_Q24, ind + 1 ), 22 ); + silk_SMULWB( maxabs_Q20 - limit_Q20, silk_SMLABB( SILK_FIX_CONST( 0.8, 10 ), SILK_FIX_CONST( 0.1, 10 ), iter ) ), + silk_MUL( maxabs_Q20, ind + 1 ), 22 ); silk_bwexpander_32( coefs_Q24, order, chirp_Q16 ); /* Convert to monic warped coefficients */ |