/*
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* Copyright (C) 2003 - 2016 Sony Corporation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "ldac.h"
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/***************************************************************************************************
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Subfunction: Process MDCT Core
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***************************************************************************************************/
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static void proc_mdct_core_ldac(
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SCALAR *p_x,
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SCALAR *p_y,
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int nlnn)
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{
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int i, j, k;
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int loop1, loop2;
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int coef, index0, index1, offset;
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int nsmpl = npow2_ldac(nlnn);
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const int *p_p;
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const SCALAR *p_w, *p_c, *p_s;
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SCALAR a_work[LDAC_MAXLSU];
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SCALAR *p_work = a_work;
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SCALAR a, b, c, d, tmp;
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SCALAR cc, cs;
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i = nlnn - LDAC_1FSLNN;
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p_w = gaa_fwin_ldac[i];
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p_c = gaa_wcos_ldac[i];
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p_s = gaa_wsin_ldac[i];
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p_p = gaa_perm_ldac[i];
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/* Windowing */
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for (i = 0; i < nsmpl>>1; i++) {
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p_work[p_p[i]] = -p_x[3*nsmpl/2-1-i] * p_w[nsmpl/2+i] - p_x[3*nsmpl/2+i] * p_w[nsmpl/2-1-i];
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p_work[p_p[nsmpl/2+i]] = p_x[i] * p_w[i] - p_x[nsmpl-1-i] * p_w[nsmpl-1-i];
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}
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/* Butterfly */
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coef = 0;
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for (i = 0; i < nlnn-1; ++i) {
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loop1 = 1 << (nlnn-2-i);
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loop2 = 1 << i;
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index0 = 0;
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index1 = 1 << (i+1);
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offset = 1 << (i+2);
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for (k = 0; k < loop2; ++k) {
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cc = p_c[coef];
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cs = p_s[coef++];
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for (j = 0; j < loop1; ++j) {
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a = p_work[index0+0];
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b = p_work[index0+1];
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c = p_work[index1+0] * cc + p_work[index1+1] * cs;
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d = p_work[index1+0] * cs - p_work[index1+1] * cc;
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p_work[index0+0] = a + c;
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p_work[index0+1] = b + d;
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p_work[index1+0] = a - c;
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p_work[index1+1] = b - d;
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index0 += offset;
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index1 += offset;
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}
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index0 += 2 - nsmpl;
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index1 += 2 - nsmpl;
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}
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}
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tmp = _scalar(1.0) / (SCALAR)(nsmpl>>1);
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for (i = 0; i < nsmpl>>1; i++) {
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cc = p_c[coef];
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cs = p_s[coef++];
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index0 = i << 1;
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a = p_work[index0] * cc + p_work[index0+1] * cs;
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b = p_work[index0] * cs - p_work[index0+1] * cc;
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p_y[index0] = a * tmp;
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p_y[nsmpl-index0-1] = b * tmp;
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}
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return;
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}
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/***************************************************************************************************
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Process MDCT
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***************************************************************************************************/
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DECLFUNC void proc_mdct_ldac(
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SFINFO *p_sfinfo,
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int nlnn)
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{
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AC *p_ac;
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int ich;
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int nchs = p_sfinfo->cfg.ch;
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for (ich = 0; ich < nchs; ich++) {
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p_ac = p_sfinfo->ap_ac[ich];
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proc_mdct_core_ldac(p_ac->p_acsub->a_time, p_ac->p_acsub->a_spec, nlnn);
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}
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return;
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}
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