inline void zap_buffer_denormals(double *buf, int bufSize) {
for(int i=0; i < bufSize; i++)
buf[i] = zap_denormal(buf[i]);
}
void EngineFilterIIR::process(const CSAMPLE* pIn, CSAMPLE* pOutput, const int iBufferSize)
{
double GAIN = coefs[0];
int i;
for (i=0; i<iBufferSize; i+=2)
{
if (order==8)
{
//8th order:
// Channel 1
xv1[0] = xv1[1]; xv1[1] = xv1[2]; xv1[2] = xv1[3]; xv1[3] = xv1[4];
xv1[4] = xv1[5]; xv1[5] = xv1[6]; xv1[6] = xv1[7]; xv1[7] = xv1[8];
xv1[8] = pIn[i]/GAIN;
yv1[0] = yv1[1]; yv1[1] = yv1[2]; yv1[2] = yv1[3]; yv1[3] = yv1[4];
yv1[4] = yv1[5]; yv1[5] = yv1[6]; yv1[6] = yv1[7]; yv1[7] = yv1[8];
yv1[8] = (xv1[0] + xv1[8]) + coefs[1] * (xv1[1] + xv1[7]) +
coefs[2] * (xv1[2] + xv1[6]) +
coefs[3] * (xv1[3] + xv1[5]) + coefs[4] * xv1[4] +
(coefs[5] * yv1[0]) + ( coefs[6] * yv1[1]) +
(coefs[7] * yv1[2]) + ( coefs[8] * yv1[3]) +
(coefs[9] * yv1[4]) + ( coefs[10] * yv1[5]) +
(coefs[11] * yv1[6]) + ( coefs[12] * yv1[7]);
// Guard against nan.
if (isnan(yv1[8])) {
Counter count("EngineFilterIIR::process yv1[8] isnan");
count.increment();
yv1[8] = 0;
}
pOutput[i] = yv1[8];
// Channel 2
xv2[0] = xv2[1]; xv2[1] = xv2[2]; xv2[2] = xv2[3]; xv2[3] = xv2[4];
xv2[4] = xv2[5]; xv2[5] = xv2[6]; xv2[6] = xv2[7]; xv2[7] = xv2[8];
xv2[8] = pIn[i+1]/GAIN;
yv2[0] = yv2[1]; yv2[1] = yv2[2]; yv2[2] = yv2[3]; yv2[3] = yv2[4];
yv2[4] = yv2[5]; yv2[5] = yv2[6]; yv2[6] = yv2[7]; yv2[7] = yv2[8];
yv2[8] = (xv2[0] + xv2[8]) + coefs[1] * (xv2[1] + xv2[7]) +
coefs[2] * (xv2[2] + xv2[6]) +
coefs[3] * (xv2[3] + xv2[5]) + coefs[4] * xv2[4] +
(coefs[5] * yv2[0]) + ( coefs[6] * yv2[1]) +
(coefs[7] * yv2[2]) + ( coefs[8] * yv2[3]) +
(coefs[9] * yv2[4]) + ( coefs[10] * yv2[5]) +
(coefs[11] * yv2[6]) + ( coefs[12] * yv2[7]);
// Guard against nan.
if (isnan(yv2[8])) {
Counter count("EngineFilterIIR::process yv2[8] isnan");
count.increment();
yv2[8] = 0;
}
pOutput[i+1] = yv2[8];
}
else if (order==2)
{
// Second order
xv1[0] = xv1[1]; xv1[1] = xv1[2];
xv1[2] = pIn[i] / GAIN;
yv1[0] = yv1[1]; yv1[1] = yv1[2];
yv1[2] = (xv1[0] + xv1[2]) + coefs[1] * xv1[1] + ( coefs[2] * yv1[0]) + (coefs[3] * yv1[1]);
pOutput[i] = yv1[2];
xv2[0] = xv2[1]; xv2[1] = xv2[2];
xv2[2] = pIn[i+1] / GAIN;
yv2[0] = yv2[1]; yv2[1] = yv2[2];
yv2[2] = (xv2[0] + xv2[2]) + coefs[1] * xv2[1] + ( coefs[2] * yv2[0]) + (coefs[3] * yv2[1]);
pOutput[i+1] = yv2[2];
}
else
{
// Fourth order
xv1[0] = xv1[1]; xv1[1] = xv1[2]; xv1[2] = xv1[3]; xv1[3] = xv1[4];
xv1[4] = pIn[i] / GAIN;
yv1[0] = yv1[1]; yv1[1] = yv1[2]; yv1[2] = yv1[3]; yv1[3] = yv1[4];
yv1[4] = (xv1[0] + xv1[4]) + coefs[1]*(xv1[1]+xv1[3]) + coefs[2] * xv1[2]
+ ( coefs[3] * yv1[0]) + ( coefs[4] * yv1[1])
+ ( coefs[5] * yv1[2]) + ( coefs[6] * yv1[3]);
pOutput[i] = yv1[4];
xv2[0] = xv2[1]; xv2[1] = xv2[2]; xv2[2] = xv2[3]; xv2[3] = xv2[4];
xv2[4] = pIn[i+1] / GAIN;
yv2[0] = yv2[1]; yv2[1] = yv2[2]; yv2[2] = yv2[3]; yv2[3] = yv2[4];
yv2[4] = (xv2[0] + xv2[4]) + coefs[1]*(xv2[1]+xv2[3]) + coefs[2] * xv2[2]
+ ( coefs[3] * yv2[0]) + ( coefs[4] * yv2[1])
+ ( coefs[5] * yv2[2]) + ( coefs[6] * yv2[3]);
pOutput[i+1] = yv2[4];
}
}
// Check for denormals
for (i=0; i<=order; ++i)
{
xv1[i] = zap_denormal(xv1[i]);
yv1[i] = zap_denormal(yv1[i]);
xv2[i] = zap_denormal(xv2[i]);
yv2[i] = zap_denormal(yv2[i]);
}
}
