convolve.c revision f3664ae9369a861ffbc2354e8e93e48983802062 
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: convolve.c
19
20	   Description:Perform the convolution between two vectors x[] and h[]
21	               and write the result in the vector y[]
22
23************************************************************************/
24
25#include "typedef.h"
26#include "basic_op.h"
27
28void Convolve (
29		Word16 x[],        /* (i)     : input vector                           */
30		Word16 h[],        /* (i)     : impulse response                       */
31		Word16 y[],        /* (o)     : output vector                          */
32		Word16 L           /* (i)     : vector size                            */
33	      )
34{
35	Word32  i, n;
36	Word16 *tmpH,*tmpX;
37	Word32 s;
38	for (n = 0; n < 64;)
39	{
40		tmpH = h+n;
41		tmpX = x;
42		i=n+1;
43		s = vo_mult32((*tmpX++), (*tmpH--));i--;
44		while(i>0)
45		{
46			s += vo_mult32((*tmpX++), (*tmpH--));
47			s += vo_mult32((*tmpX++), (*tmpH--));
48			s += vo_mult32((*tmpX++), (*tmpH--));
49			s += vo_mult32((*tmpX++), (*tmpH--));
50			i -= 4;
51		}
52		y[n] = ((s<<1) + 0x8000)>>16;
53		n++;
54
55		tmpH = h+n;
56		tmpX = x;
57		i=n+1;
58		s =  vo_mult32((*tmpX++), (*tmpH--));i--;
59		s += vo_mult32((*tmpX++), (*tmpH--));i--;
60
61		while(i>0)
62		{
63			s += vo_mult32((*tmpX++), (*tmpH--));
64			s += vo_mult32((*tmpX++), (*tmpH--));
65			s += vo_mult32((*tmpX++), (*tmpH--));
66			s += vo_mult32((*tmpX++), (*tmpH--));
67			i -= 4;
68		}
69		y[n] = ((s<<1) + 0x8000)>>16;
70		n++;
71
72		tmpH = h+n;
73		tmpX = x;
74		i=n+1;
75		s =  vo_mult32((*tmpX++), (*tmpH--));i--;
76		s += vo_mult32((*tmpX++), (*tmpH--));i--;
77		s += vo_mult32((*tmpX++), (*tmpH--));i--;
78
79		while(i>0)
80		{
81			s += vo_mult32((*tmpX++), (*tmpH--));
82			s += vo_mult32((*tmpX++), (*tmpH--));
83			s += vo_mult32((*tmpX++), (*tmpH--));
84			s += vo_mult32((*tmpX++), (*tmpH--));
85			i -= 4;
86		}
87		y[n] = ((s<<1) + 0x8000)>>16;
88		n++;
89
90		s = 0;
91		tmpH = h+n;
92		tmpX = x;
93		i=n+1;
94		while(i>0)
95		{
96			s += vo_mult32((*tmpX++), (*tmpH--));
97			s += vo_mult32((*tmpX++), (*tmpH--));
98			s += vo_mult32((*tmpX++), (*tmpH--));
99			s += vo_mult32((*tmpX++), (*tmpH--));
100			i -= 4;
101		}
102		y[n] = ((s<<1) + 0x8000)>>16;
103		n++;
104	}
105	return;
106}
107
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110