61 lines
1.5 KiB
C
61 lines
1.5 KiB
C
/*
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* Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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/*
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* This file contains the function WebRtcSpl_ReflCoefToLpc().
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* The description header can be found in signal_processing_library.h
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*
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*/
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#include "signal_processing_library.h"
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void WebRtcSpl_ReflCoefToLpc(G_CONST WebRtc_Word16 *k, int use_order, WebRtc_Word16 *a)
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{
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WebRtc_Word16 any[WEBRTC_SPL_MAX_LPC_ORDER + 1];
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WebRtc_Word16 *aptr, *aptr2, *anyptr;
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G_CONST WebRtc_Word16 *kptr;
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int m, i;
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kptr = k;
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*a = 4096; // i.e., (Word16_MAX >> 3)+1.
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*any = *a;
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a[1] = WEBRTC_SPL_RSHIFT_W16((*k), 3);
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for (m = 1; m < use_order; m++)
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{
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kptr++;
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aptr = a;
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aptr++;
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aptr2 = &a[m];
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anyptr = any;
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anyptr++;
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any[m + 1] = WEBRTC_SPL_RSHIFT_W16((*kptr), 3);
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for (i = 0; i < m; i++)
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{
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*anyptr = (*aptr)
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+ (WebRtc_Word16)WEBRTC_SPL_MUL_16_16_RSFT((*aptr2), (*kptr), 15);
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anyptr++;
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aptr++;
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aptr2--;
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}
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aptr = a;
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anyptr = any;
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for (i = 0; i < (m + 2); i++)
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{
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*aptr = *anyptr;
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aptr++;
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anyptr++;
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}
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}
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}
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