// Scale the next wave sample and place in centre
newsample = (newsample / 2) + 64; 

// generate the BTc bit,
// does the BTc wave need to react UP or DOWN to follow it?
if(newsample > lastbtc)
{
   newbit = 1;                 // BTc must move UP
   
   dist = (256 - lastbtc);     // calc total distance to charge
   dist = (dist / 4);          // BTc4, only charge 1/4 distance
   lastbtc = (lastbtc + dist); // where it charges up to
   goto done;
}
else
{
   newbit = 0;                 // BTc must move DOWN

   dist = lastbtc;             // calc total distance to charge
   dist = (dist / 4);          // BTc4, only charge 1/4 distance
   lastbtc = (lastbtc - dist); // where it charges down to
   goto done;
}

// Scale the next wave sample and place in centre
newsample = (newsample / 2) + 64; 

// generate a "1" (high) outcome
dist = (256 - lastbtc);     // calc total distance to charge
dist = (dist / 4);          // BTc4, only charge 1/4 distance
highbtc = (lastbtc + dist); // where it charges up to

// generate a "0" (low) outcome
dist = lastbtc;             // calc total distance to charge
dist = (dist / 4);          // BTc4, only charge 1/4 distance
lowbtc = (lastbtc - dist);  // where it charges down to

// calc distance from high outcome (up or down) to new sample
if(highbtc > newsample) disthigh = (highbtc - newsample);
else                    disthigh = (newsample - highbtc);

// calc distance from low outcome (up or down) to new sample
if(lowbtc > newsample)  distlow = (lowbtc - newsample);
else                    distlow = (newsample - lowbtc);

// see which outcome is closest to new sample and generate the bit
if(disthigh > distlow)    // low is closest
{
   newbit=0;
   lastbtc = lowbtc;
}
else                      // else high is closest
{
   newbit=1;
   lastbtc = highbtc;
}
goto done;