g_pitch.c revision 5d5c3a132bb446ac78a37dfaac24a46cacf0dd73 
1/*
2 ** Copyright 2003-2010, VisualOn, Inc.
3 **
4 ** Licensed under the Apache License, Version 2.0 (the "License");
5 ** you may not use this file except in compliance with the License.
6 ** You may obtain a copy of the License at
7 **
8 **     http://www.apache.org/licenses/LICENSE-2.0
9 **
10 ** Unless required by applicable law or agreed to in writing, software
11 ** distributed under the License is distributed on an "AS IS" BASIS,
12 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 ** See the License for the specific language governing permissions and
14 ** limitations under the License.
15 */
16
17/***********************************************************************
18*      File: g_pitch.c                                                 *
19*                                                                      *
20*      Description:Compute the gain of pitch. Result in Q12        *
21*                  if(gain < 0) gain = 0                           *
22*                  if(gain > 1.2) gain = 1.2           *
23************************************************************************/
24
25#include "typedef.h"
26#include "basic_op.h"
27#include "math_op.h"
28
29Word16 G_pitch(                            /* (o) Q14 : Gain of pitch lag saturated to 1.2   */
30        Word16 xn[],                          /* (i)     : Pitch target.                        */
31        Word16 y1[],                          /* (i)     : filtered adaptive codebook.          */
32        Word16 g_coeff[],                     /* : Correlations need for gain quantization.     */
33        Word16 L_subfr                        /* : Length of subframe.                          */
34          )
35{
36    Word32 i;
37    Word16 xy, yy, exp_xy, exp_yy, gain;
38    /* Compute scalar product <y1[],y1[]> */
39#ifdef ASM_OPT                  /* asm optimization branch */
40    /* Compute scalar product <xn[],y1[]> */
41    xy = extract_h(Dot_product12_asm(xn, y1, L_subfr, &exp_xy));
42    yy = extract_h(Dot_product12_asm(y1, y1, L_subfr, &exp_yy));
43
44#else
45    /* Compute scalar product <xn[],y1[]> */
46    xy = extract_h(Dot_product12(xn, y1, L_subfr, &exp_xy));
47    yy = extract_h(Dot_product12(y1, y1, L_subfr, &exp_yy));
48
49#endif
50
51    g_coeff[0] = yy;
52    g_coeff[1] = exp_yy;
53    g_coeff[2] = xy;
54    g_coeff[3] = exp_xy;
55
56    /* If (xy < 0) gain = 0 */
57    if (xy < 0)
58        return ((Word16) 0);
59
60    /* compute gain = xy/yy */
61
62    xy >>= 1;                       /* Be sure xy < yy */
63    gain = div_s(xy, yy);
64
65    i = exp_xy;
66    i -= exp_yy;
67
68    gain = shl(gain, i);
69
70    /* if (gain > 1.2) gain = 1.2  in Q14 */
71    if(gain > 19661)
72    {
73        gain = 19661;
74    }
75    return (gain);
76}
77
78
79
80