/*
 ** Copyright 2003-2010, VisualOn, Inc.
 **
 ** Licensed under the Apache License, Version 2.0 (the "License");
 ** you may not use this file except in compliance with the License.
 ** You may obtain a copy of the License at
 **
 **     http://www.apache.org/licenses/LICENSE-2.0
 **
 ** Unless required by applicable law or agreed to in writing, software
 ** distributed under the License is distributed on an "AS IS" BASIS,
 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 ** See the License for the specific language governing permissions and
 ** limitations under the License.
 */

/***********************************************************************
       File: convolve.c

       Description:Perform the convolution between two vectors x[] and h[]
                   and write the result in the vector y[]

************************************************************************/

#include "typedef.h"
#include "basic_op.h"

#define UNUSED(x) (void)(x)

void Convolve (
        Word16 x[],        /* (i)     : input vector                           */
        Word16 h[],        /* (i)     : impulse response                       */
        Word16 y[],        /* (o)     : output vector                          */
        Word16 L           /* (i)     : vector size                            */
          )
{
    Word32  i, n;
    Word16 *tmpH,*tmpX;
    Word32 s;
        UNUSED(L);

    for (n = 0; n < 64;)
    {
        tmpH = h+n;
        tmpX = x;
        i=n+1;
        s = vo_mult32((*tmpX++), (*tmpH--));i--;
        while(i>0)
        {
            s = L_add(s, vo_mult32((*tmpX++), (*tmpH--)));
            s = L_add(s, vo_mult32((*tmpX++), (*tmpH--)));
            s = L_add(s, vo_mult32((*tmpX++), (*tmpH--)));
            s = L_add(s, vo_mult32((*tmpX++), (*tmpH--)));
            i -= 4;
        }
        y[n] = voround(L_shl(s, 1));
        n++;

        tmpH = h+n;
        tmpX = x;
        i=n+1;
        s =  vo_mult32((*tmpX++), (*tmpH--));
        i--;
        s = L_add(s, vo_mult32((*tmpX++), (*tmpH--)));
        i--;

        while(i>0)
        {
            s = L_add(s, vo_mult32((*tmpX++), (*tmpH--)));
            s = L_add(s, vo_mult32((*tmpX++), (*tmpH--)));
            s = L_add(s, vo_mult32((*tmpX++), (*tmpH--)));
            s = L_add(s, vo_mult32((*tmpX++), (*tmpH--)));
            i -= 4;
        }
        y[n] = voround(L_shl(s, 1));
        n++;

        tmpH = h+n;
        tmpX = x;
        i=n+1;
        s =  vo_mult32((*tmpX++), (*tmpH--));
        i--;
        s = L_add(s, vo_mult32((*tmpX++), (*tmpH--)));
        i--;
        s = L_add(s, vo_mult32((*tmpX++), (*tmpH--)));
        i--;

        while(i>0)
        {
            s = L_add(s, vo_mult32((*tmpX++), (*tmpH--)));
            s = L_add(s, vo_mult32((*tmpX++), (*tmpH--)));
            s = L_add(s, vo_mult32((*tmpX++), (*tmpH--)));
            s = L_add(s, vo_mult32((*tmpX++), (*tmpH--)));
            i -= 4;
        }
        y[n] = voround(L_shl(s, 1));
        n++;

        s = 0;
        tmpH = h+n;
        tmpX = x;
        i=n+1;
        while(i>0)
        {
            s = L_add(s, vo_mult32((*tmpX++), (*tmpH--)));
            s = L_add(s, vo_mult32((*tmpX++), (*tmpH--)));
            s = L_add(s, vo_mult32((*tmpX++), (*tmpH--)));
            s = L_add(s, vo_mult32((*tmpX++), (*tmpH--)));
            i -= 4;
        }
        y[n] = voround(L_shl(s, 1));
        n++;
    }
    return;
}