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/*
* Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
/******************************************************************
iLBC Speech Coder ANSI-C Source Code
WebRtcIlbcfix_Window32W32.c
******************************************************************/
#include "defines.h"
/*----------------------------------------------------------------*
* window multiplication
*---------------------------------------------------------------*/
void WebRtcIlbcfix_Window32W32(
int32_t *z, /* Output */
int32_t *x, /* Input (same domain as Output)*/
const int32_t *y, /* Q31 Window */
int16_t N /* length to process */
) {
int16_t i;
int16_t x_low, x_hi, y_low, y_hi;
int16_t left_shifts;
int32_t temp;
left_shifts = (int16_t)WebRtcSpl_NormW32(x[0]);
WebRtcSpl_VectorBitShiftW32(x, N, x, (int16_t)(-left_shifts));
/* The double precision numbers use a special representation:
* w32 = hi<<16 + lo<<1
*/
for (i = 0; i < N; i++) {
/* Extract higher bytes */
x_hi = (int16_t) WEBRTC_SPL_RSHIFT_W32(x[i], 16);
y_hi = (int16_t) WEBRTC_SPL_RSHIFT_W32(y[i], 16);
/* Extract lower bytes, defined as (w32 - hi<<16)>>1 */
temp = WEBRTC_SPL_LSHIFT_W32((int32_t)x_hi, 16);
x_low = (int16_t) WEBRTC_SPL_RSHIFT_W32((x[i] - temp), 1);
temp = WEBRTC_SPL_LSHIFT_W32((int32_t)y_hi, 16);
y_low = (int16_t) WEBRTC_SPL_RSHIFT_W32((y[i] - temp), 1);
/* Calculate z by a 32 bit multiplication using both low and high from x and y */
temp = WEBRTC_SPL_LSHIFT_W32(WEBRTC_SPL_MUL_16_16(x_hi, y_hi), 1);
temp = (temp + (WEBRTC_SPL_MUL_16_16_RSFT(x_hi, y_low, 14)));
z[i] = (temp + (WEBRTC_SPL_MUL_16_16_RSFT(x_low, y_hi, 14)));
}
WebRtcSpl_VectorBitShiftW32(z, N, z, left_shifts);
return;
}
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