Finding the counter in al loop

A simple way to do this is to have two extra variables, one to track the crossing from 0 to 1 and the other to track the crossing from 1 to 0. The thing you will need to take into consideration is that you only want to increment these values when Zero_Cross changes. As an example:

int oneToZero;
int zeroToOne;
int Zero_Cross;
if (BackFromPowerLoss > 20)
{
  if (Zero_Cross == 1)
  {
    oneToZero++;
  }
  Zero_Cross = 0;
}

You should be able to fill the rest in from that snippet. The key thing is that you need to check what the previous value of Zero_Cross is before you change it.

static int u8PowerLoss_old = 0;
int Zero_Cross;

if(BackFromPowerLoss > 20)
{
Zero_Cross =0 ;
}
else
{
Zero_Cross = 1 ;
}
   u8PowerLoss_old = Zero_Cross; // this is a static variable , 
}