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26***********************************************************************/
27
28#ifdef HAVE_CONFIG_H
29#include "config.h"
30#endif
31
32#include "main.h"
33
34/* Compute quantization errors for an LPC_order element input vector for a VQ codebook */
35void silk_NLSF_VQ(
36    opus_int32                  err_Q26[],                      /* O    Quantization errors [K]                     */
37    const opus_int16            in_Q15[],                       /* I    Input vectors to be quantized [LPC_order]   */
38    const opus_uint8            pCB_Q8[],                       /* I    Codebook vectors [K*LPC_order]              */
39    const opus_int              K,                              /* I    Number of codebook vectors                  */
40    const opus_int              LPC_order                       /* I    Number of LPCs                              */
41)
42{
43    opus_int        i, m;
44    opus_int32      diff_Q15, sum_error_Q30, sum_error_Q26;
45
46    silk_assert( LPC_order <= 16 );
47    silk_assert( ( LPC_order & 1 ) == 0 );
48
49    /* Loop over codebook */
50    for( i = 0; i < K; i++ ) {
51        sum_error_Q26 = 0;
52        for( m = 0; m < LPC_order; m += 2 ) {
53            /* Compute weighted squared quantization error for index m */
54            diff_Q15 = silk_SUB_LSHIFT32( in_Q15[ m ], (opus_int32)*pCB_Q8++, 7 ); /* range: [ -32767 : 32767 ]*/
55            sum_error_Q30 = silk_SMULBB( diff_Q15, diff_Q15 );
56
57            /* Compute weighted squared quantization error for index m + 1 */
58            diff_Q15 = silk_SUB_LSHIFT32( in_Q15[m + 1], (opus_int32)*pCB_Q8++, 7 ); /* range: [ -32767 : 32767 ]*/
59            sum_error_Q30 = silk_SMLABB( sum_error_Q30, diff_Q15, diff_Q15 );
60
61            sum_error_Q26 = silk_ADD_RSHIFT32( sum_error_Q26, sum_error_Q30, 4 );
62
63            silk_assert( sum_error_Q26 >= 0 );
64            silk_assert( sum_error_Q30 >= 0 );
65        }
66        err_Q26[ i ] = sum_error_Q26;
67    }
68}
69