module: int_first_ord_diff
parameters:
inputs: double in, double clk
outputs:  double out
static_variables: double prev_in
classes: EdgeDetect clkedge()
init: 
prev_in = 0;
code:
if (clkedge.inp(clk))
   {
    out = floor(in+0.5) - prev_in;
    prev_in = floor(in+0.5);
   }
