TMS320F28335 Compiler CCSv3.3

Hallo,

I use Code generation tools v5.2.11!

if I remove the volatile in this function, I got errors in calculating from time to time.

It must be the for slope?

static doesn't work!

Any idea? Stack problem?

Of cause all variables are not in use outside of this function.

float32 FilterLinReg (objMavg *p, float32 p_fDataX, float32 p_fDataY)
{
    volatile Uint16 i, j, k;
    volatile float32 fSumX, fSumY, fSumXx, fSumXy;
    fSumX = fSumY = fSumXy = fSumXx = 0.0;
    // check if memory is complete and mark as FULL
    if (p->uK >= p->uN)
    {
        p->uK    = 0;
        p->fFull = FILTER_FULL;
    }
    // store actual value to next position
    *(p->pfData + p->uK) = p_fDataY;
    // index to next position
    p->uK++;


    // regression length at start is shorter
    if (p->fFull == FILTER_FULL)
    {
        j = p->uN;
        // filter full, start at uK value
        k = p->uK;
    }
    else
    {
        j = p->uK;
        // filter not full, start at 0 value
        k = 0;
    }

    // calculate REGRESSION sums over the actual memory
    if( j>1)
    {
        for(i = 0; i <= (j-1); i++)
        {
            if(k >= p->uN)
                k=0;
            // sum of all y values
            // 23.02.16 bug ??? fSumY += *(p->pfData + i);
            fSumY += *(p->pfData + k);
            // sum of all x values
            fSumX += (i) * p_fDataX;
            // sum of all y * x values
            fSumXy += *(p->pfData + k) * ((i) * p_fDataX);
            // sum of all x² values    
            fSumXx += ((i) * p_fDataX) * ((i) * p_fDataX);
            k++;
        }
        // calculate regression y = a + bx, at the moment only b
        p->fY = (fSumXy-((fSumX*fSumY)/(float)j)) / (fSumXx-((fSumX*fSumX)/(float)j));
         }
    else
    {
        p->fY = 0.0;
    }
    return p->fY;
    //return fSumX;
}



/*!
\fn    void FiltLinRegInit(objMavg *p, float32 *data, const Uint16 n)
\brief Initilisation of Linear Regression with up to 2^16 values.
                   
\author    R. Koester
\date        27.01.2016
\param[in]  *p - pointer to filter object
            data - adress of data buffer
            n - length of data buffer
\return    void

\details Changes:

*/
void FiltLinRegInit(objMavg *p, float32 *data, const Uint16 n)
{
    // set Buffer pointer to data array
    p->pfData = data;
    // store number of values (size of dataarray)
    p->uN    = n;
    // reset data array to 0.0
    for (p->uK = 0; p->uK < p->uN; p->uK++)
    {
        *(p->pfData + p->uK) = ((float32) 0.0);
    }
    // delete actual counter, sum and Full semaphore
    p->uK    = ((Uint32) 0);
    //p->fSum  = ((float32) 0.0);
    p->fFull = ((Uint16) 0);
}