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27
28 #ifdef HAVE_CONFIG_H
29 #include "config.h"
30 #endif
31
32 #include "main_FIX.h"
33
34 #define QC 10
35 #define QS 14
36
37 /* Autocorrelations for a warped frequency axis */
silk_warped_autocorrelation_FIX(opus_int32 * corr,opus_int * scale,const opus_int16 * input,const opus_int warping_Q16,const opus_int length,const opus_int order)38 void silk_warped_autocorrelation_FIX(
39 opus_int32 *corr, /* O Result [order + 1] */
40 opus_int *scale, /* O Scaling of the correlation vector */
41 const opus_int16 *input, /* I Input data to correlate */
42 const opus_int warping_Q16, /* I Warping coefficient */
43 const opus_int length, /* I Length of input */
44 const opus_int order /* I Correlation order (even) */
45 )
46 {
47 opus_int n, i, lsh;
48 opus_int32 tmp1_QS, tmp2_QS;
49 opus_int32 state_QS[ MAX_SHAPE_LPC_ORDER + 1 ] = { 0 };
50 opus_int64 corr_QC[ MAX_SHAPE_LPC_ORDER + 1 ] = { 0 };
51
52 /* Order must be even */
53 silk_assert( ( order & 1 ) == 0 );
54 silk_assert( 2 * QS - QC >= 0 );
55
56 /* Loop over samples */
57 for( n = 0; n < length; n++ ) {
58 tmp1_QS = silk_LSHIFT32( (opus_int32)input[ n ], QS );
59 /* Loop over allpass sections */
60 for( i = 0; i < order; i += 2 ) {
61 /* Output of allpass section */
62 tmp2_QS = silk_SMLAWB( state_QS[ i ], state_QS[ i + 1 ] - tmp1_QS, warping_Q16 );
63 state_QS[ i ] = tmp1_QS;
64 corr_QC[ i ] += silk_RSHIFT64( silk_SMULL( tmp1_QS, state_QS[ 0 ] ), 2 * QS - QC );
65 /* Output of allpass section */
66 tmp1_QS = silk_SMLAWB( state_QS[ i + 1 ], state_QS[ i + 2 ] - tmp2_QS, warping_Q16 );
67 state_QS[ i + 1 ] = tmp2_QS;
68 corr_QC[ i + 1 ] += silk_RSHIFT64( silk_SMULL( tmp2_QS, state_QS[ 0 ] ), 2 * QS - QC );
69 }
70 state_QS[ order ] = tmp1_QS;
71 corr_QC[ order ] += silk_RSHIFT64( silk_SMULL( tmp1_QS, state_QS[ 0 ] ), 2 * QS - QC );
72 }
73
74 lsh = silk_CLZ64( corr_QC[ 0 ] ) - 35;
75 lsh = silk_LIMIT( lsh, -12 - QC, 30 - QC );
76 *scale = -( QC + lsh );
77 silk_assert( *scale >= -30 && *scale <= 12 );
78 if( lsh >= 0 ) {
79 for( i = 0; i < order + 1; i++ ) {
80 corr[ i ] = (opus_int32)silk_CHECK_FIT32( silk_LSHIFT64( corr_QC[ i ], lsh ) );
81 }
82 } else {
83 for( i = 0; i < order + 1; i++ ) {
84 corr[ i ] = (opus_int32)silk_CHECK_FIT32( silk_RSHIFT64( corr_QC[ i ], -lsh ) );
85 }
86 }
87 silk_assert( corr_QC[ 0 ] >= 0 ); /* If breaking, decrease QC*/
88 }
89