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27
28 #include "SKP_Silk_main_FIX.h"
29
SKP_Silk_LTP_analysis_filter_FIX(SKP_int16 * LTP_res,const SKP_int16 * x,const SKP_int16 LTPCoef_Q14[LTP_ORDER * NB_SUBFR],const SKP_int pitchL[NB_SUBFR],const SKP_int32 invGains_Qxx[NB_SUBFR],const SKP_int Qxx,const SKP_int subfr_length,const SKP_int pre_length)30 void SKP_Silk_LTP_analysis_filter_FIX(
31 SKP_int16 *LTP_res, /* O: LTP residual signal of length NB_SUBFR * ( pre_length + subfr_length ) */
32 const SKP_int16 *x, /* I: Pointer to input signal with at least max( pitchL ) preceeding samples */
33 const SKP_int16 LTPCoef_Q14[ LTP_ORDER * NB_SUBFR ],/* I: LTP_ORDER LTP coefficients for each NB_SUBFR subframe */
34 const SKP_int pitchL[ NB_SUBFR ], /* I: Pitch lag, one for each subframe */
35 const SKP_int32 invGains_Qxx[ NB_SUBFR ], /* I: Inverse quantization gains, one for each subframe */
36 const SKP_int Qxx, /* I: Inverse quantization gains Q domain */
37 const SKP_int subfr_length, /* I: Length of each subframe */
38 const SKP_int pre_length /* I: Length of the preceeding samples starting at &x[0] for each subframe */
39 )
40 {
41 const SKP_int16 *x_ptr, *x_lag_ptr;
42 SKP_int16 Btmp_Q14[ LTP_ORDER ];
43 SKP_int16 *LTP_res_ptr;
44 SKP_int k, i, j;
45 SKP_int32 LTP_est;
46
47 x_ptr = x;
48 LTP_res_ptr = LTP_res;
49 for( k = 0; k < NB_SUBFR; k++ ) {
50
51 x_lag_ptr = x_ptr - pitchL[ k ];
52 for( i = 0; i < LTP_ORDER; i++ ) {
53 Btmp_Q14[ i ] = LTPCoef_Q14[ k * LTP_ORDER + i ];
54 }
55
56 /* LTP analysis FIR filter */
57 for( i = 0; i < subfr_length + pre_length; i++ ) {
58 LTP_res_ptr[ i ] = x_ptr[ i ];
59
60 /* Long-term prediction */
61 LTP_est = SKP_SMULBB( x_lag_ptr[ LTP_ORDER / 2 ], Btmp_Q14[ 0 ] );
62 for( j = 1; j < LTP_ORDER; j++ ) {
63 LTP_est = SKP_SMLABB_ovflw( LTP_est, x_lag_ptr[ LTP_ORDER / 2 - j ], Btmp_Q14[ j ] );
64 }
65 LTP_est = SKP_RSHIFT_ROUND( LTP_est, 14 ); // round and -> Q0
66
67 /* Subtract long-term prediction */
68 LTP_res_ptr[ i ] = ( SKP_int16 )SKP_SAT16( ( SKP_int32 )x_ptr[ i ] - LTP_est );
69
70 /* Scale residual */
71 if( Qxx == 16 ) {
72 LTP_res_ptr[ i ] = SKP_SMULWB( invGains_Qxx[ k ], LTP_res_ptr[ i ] );
73 } else {
74 LTP_res_ptr[ i ] = ( SKP_int16 )SKP_CHECK_FIT16( SKP_RSHIFT64( SKP_SMULL( invGains_Qxx[ k ], LTP_res_ptr[ i ] ), Qxx ) );
75 }
76
77 x_lag_ptr++;
78 }
79
80 /* Update pointers */
81 LTP_res_ptr += subfr_length + pre_length;
82 x_ptr += subfr_length;
83 }
84 }
85
86