/*---------------------------------------------------------
 *
 * Finite Impulse Response (FIR) Filter (C-RAM)
 *
 */

#include <cram.h>
#include"fir.h"


// PE0 has least delay
// highest PE's input is tied to ground

cuint8 weights[TAPSperPE];      // [0] is least delayed

cuint16 runningSum[TAPSperPE + 1];      // [highest] from previous PE

long int fir(int in)
{
    int j;

    // get runningSum from neighbour
    runningSum[TAPSperPE].cshiftx(-1, runningSum[0]);

    for (j = TAPSperPE-1; j >= 0; j--)  // inner product of weights
        runningSum[j] = runningSum[j + 1] + weights[j] * in;

    return (runningSum[0][0]);
}