63 lines
1.9 KiB
C
63 lines
1.9 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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iLBC Speech Coder ANSI-C Source Code
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WebRtcIlbcfix_Window32W32.c
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******************************************************************/
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#include "modules/audio_coding/codecs/ilbc/defines.h"
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/*----------------------------------------------------------------*
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* window multiplication
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*---------------------------------------------------------------*/
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void WebRtcIlbcfix_Window32W32(
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int32_t *z, /* Output */
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int32_t *x, /* Input (same domain as Output)*/
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const int32_t *y, /* Q31 Window */
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size_t N /* length to process */
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) {
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size_t i;
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int16_t x_low, x_hi, y_low, y_hi;
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int16_t left_shifts;
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int32_t temp;
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left_shifts = (int16_t)WebRtcSpl_NormW32(x[0]);
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WebRtcSpl_VectorBitShiftW32(x, N, x, (int16_t)(-left_shifts));
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/* The double precision numbers use a special representation:
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* w32 = hi<<16 + lo<<1
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*/
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for (i = 0; i < N; i++) {
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/* Extract higher bytes */
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x_hi = (int16_t)(x[i] >> 16);
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y_hi = (int16_t)(y[i] >> 16);
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/* Extract lower bytes, defined as (w32 - hi<<16)>>1 */
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x_low = (int16_t)((x[i] - (x_hi << 16)) >> 1);
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y_low = (int16_t)((y[i] - (y_hi << 16)) >> 1);
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/* Calculate z by a 32 bit multiplication using both low and high from x and y */
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temp = ((x_hi * y_hi) << 1) + ((x_hi * y_low) >> 14);
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z[i] = temp + ((x_low * y_hi) >> 14);
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}
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WebRtcSpl_VectorBitShiftW32(z, N, z, left_shifts);
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return;
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}
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