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_CbMemEnergyCalc.c
16
17******************************************************************/
18
19#include "defines.h"
20
21/* Compute the energy of the rest of the cb memory
22 * by step wise adding and subtracting the next
23 * sample and the last sample respectively */
24void WebRtcIlbcfix_CbMemEnergyCalc(
25    int32_t energy,   /* (i) input start energy */
26    int16_t range,   /* (i) number of iterations */
27    int16_t *ppi,   /* (i) input pointer 1 */
28    int16_t *ppo,   /* (i) input pointer 2 */
29    int16_t *energyW16,  /* (o) Energy in the CB vectors */
30    int16_t *energyShifts, /* (o) Shift value of the energy */
31    int16_t scale,   /* (i) The scaling of all energy values */
32    int16_t base_size  /* (i) Index to where the energy values should be stored */
33                                   )
34{
35  int16_t j,shft;
36  int32_t tmp;
37  int16_t *eSh_ptr;
38  int16_t *eW16_ptr;
39
40
41  eSh_ptr  = &energyShifts[1+base_size];
42  eW16_ptr = &energyW16[1+base_size];
43
44  for(j=0;j<range-1;j++) {
45
46    /* Calculate next energy by a +/-
47       operation on the edge samples */
48    tmp  = WEBRTC_SPL_MUL_16_16(*ppi, *ppi);
49    tmp -= WEBRTC_SPL_MUL_16_16(*ppo, *ppo);
50    energy += WEBRTC_SPL_RSHIFT_W32(tmp, scale);
51    energy = WEBRTC_SPL_MAX(energy, 0);
52
53    ppi--;
54    ppo--;
55
56    /* Normalize the energy into a int16_t and store
57       the number of shifts */
58
59    shft = (int16_t)WebRtcSpl_NormW32(energy);
60    *eSh_ptr++ = shft;
61
62    tmp = WEBRTC_SPL_LSHIFT_W32(energy, shft);
63    *eW16_ptr++ = (int16_t)WEBRTC_SPL_RSHIFT_W32(tmp, 16);
64  }
65}
66