1 /*
2 * Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
3 *
4 * Use of this source code is governed by a BSD-style license
5 * that can be found in the LICENSE file in the root of the source
6 * tree. An additional intellectual property rights grant can be found
7 * in the file PATENTS. All contributing project authors may
8 * be found in the AUTHORS file in the root of the source tree.
9 */
10
11 /******************************************************************
12
13 iLBC Speech Coder ANSI-C Source Code
14
15 WebRtcIlbcfix_Window32W32.c
16
17 ******************************************************************/
18
19 #include "modules/audio_coding/codecs/ilbc/window32_w32.h"
20
21 #include "modules/audio_coding/codecs/ilbc/defines.h"
22
23 /*----------------------------------------------------------------*
24 * window multiplication
25 *---------------------------------------------------------------*/
26
WebRtcIlbcfix_Window32W32(int32_t * z,int32_t * x,const int32_t * y,size_t N)27 void WebRtcIlbcfix_Window32W32(
28 int32_t *z, /* Output */
29 int32_t *x, /* Input (same domain as Output)*/
30 const int32_t *y, /* Q31 Window */
31 size_t N /* length to process */
32 ) {
33 size_t i;
34 int16_t x_low, x_hi, y_low, y_hi;
35 int16_t left_shifts;
36 int32_t temp;
37
38 left_shifts = (int16_t)WebRtcSpl_NormW32(x[0]);
39 WebRtcSpl_VectorBitShiftW32(x, N, x, (int16_t)(-left_shifts));
40
41
42 /* The double precision numbers use a special representation:
43 * w32 = hi<<16 + lo<<1
44 */
45 for (i = 0; i < N; i++) {
46 /* Extract higher bytes */
47 x_hi = (int16_t)(x[i] >> 16);
48 y_hi = (int16_t)(y[i] >> 16);
49
50 /* Extract lower bytes, defined as (w32 - hi<<16)>>1 */
51 x_low = (int16_t)((x[i] - (x_hi << 16)) >> 1);
52
53 y_low = (int16_t)((y[i] - (y_hi << 16)) >> 1);
54
55 /* Calculate z by a 32 bit multiplication using both low and high from x and y */
56 temp = ((x_hi * y_hi) << 1) + ((x_hi * y_low) >> 14);
57
58 z[i] = temp + ((x_low * y_hi) >> 14);
59 }
60
61 WebRtcSpl_VectorBitShiftW32(z, N, z, left_shifts);
62
63 return;
64 }
65