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//#ifdef HAVE_CONFIG_H
#include "../../config.h"
//#endif

#include "main_FIX.h"

/* Residual energy: nrg = wxx - 2 * wXx * c + c' * wXX * c */
opus_int32 silk_residual_energy16_covar_FIX(
    const opus_int16                *c,                                     /* I    Prediction vector                                                           */
    const opus_int32                *wXX,                                   /* I    Correlation matrix                                                          */
    const opus_int32                *wXx,                                   /* I    Correlation vector                                                          */
    opus_int32                      wxx,                                    /* I    Signal energy                                                               */
    opus_int                        D,                                      /* I    Dimension                                                                   */
    opus_int                        cQ                                      /* I    Q value for c vector 0 - 15                                                 */
) {
    opus_int   i, j, lshifts, Qxtra;
    opus_int32 c_max, w_max, tmp, tmp2, nrg;
    opus_int   cn[ MAX_MATRIX_SIZE ];
    const opus_int32 *pRow;

    /* Safety checks */
    celt_assert(D >=  0);
    celt_assert(D <= 16);
    celt_assert(cQ >  0);
    celt_assert(cQ < 16);

    lshifts = 16 - cQ;
    Qxtra = lshifts;

    c_max = 0;
    for (i = 0; i < D; i++) {
        c_max = silk_max_32(c_max, silk_abs((opus_int32)c[ i ]));
    }
    Qxtra = silk_min_int(Qxtra, silk_CLZ32(c_max) - 17);

    w_max = silk_max_32(wXX[ 0 ], wXX[ D * D - 1 ]);
    Qxtra = silk_min_int(Qxtra, silk_CLZ32(silk_MUL(D, silk_RSHIFT(silk_SMULWB(w_max, c_max), 4))) - 5);
    Qxtra = silk_max_int(Qxtra, 0);
    for (i = 0; i < D; i++) {
        cn[ i ] = silk_LSHIFT((opus_int)c[ i ], Qxtra);
        silk_assert(silk_abs(cn[i]) <= (silk_int16_MAX + 1));     /* Check that silk_SMLAWB can be used */
    }
    lshifts -= Qxtra;

    /* Compute wxx - 2 * wXx * c */
    tmp = 0;
    for (i = 0; i < D; i++) {
        tmp = silk_SMLAWB(tmp, wXx[ i ], cn[ i ]);
    }
    nrg = silk_RSHIFT(wxx, 1 + lshifts) - tmp;                           /* Q: -lshifts - 1 */

    /* Add c' * wXX * c, assuming wXX is symmetric */
    tmp2 = 0;
    for (i = 0; i < D; i++) {
        tmp = 0;
        pRow = &wXX[ i * D ];
        for (j = i + 1; j < D; j++) {
            tmp = silk_SMLAWB(tmp, pRow[ j ], cn[ j ]);
        }
        tmp  = silk_SMLAWB(tmp,  silk_RSHIFT(pRow[ i ], 1), cn[ i ]);
        tmp2 = silk_SMLAWB(tmp2, tmp,                        cn[ i ]);
    }
    nrg = silk_ADD_LSHIFT32(nrg, tmp2, lshifts);                         /* Q: -lshifts - 1 */

    /* Keep one bit free always, because we add them for LSF interpolation */
    if (nrg < 1) {
        nrg = 1;
    } else if (nrg > silk_RSHIFT(silk_int32_MAX, lshifts + 2)) {
        nrg = silk_int32_MAX >> 1;
    } else {
        nrg = silk_LSHIFT(nrg, lshifts + 1);                             /* Q0 */
    }
    return nrg;

}
