// tbmul8c.e  a test circuit for bmul8c
//           uses add4c.e and bmul8c.e files

// included is an 8 bit counter to test some 256 cases

// counter8.e a 8 bit counter
// cntr[8] is the 8 bits to be counted
// clk is the system clock      (initialize to 1)
define counter8(cntr[8], clk)
circuits
  cntr[0] <= ~cntr[0] on falling clk;
  cntr[1] <= ~cntr[1] on falling cntr[0];
  cntr[2] <= ~cntr[2] on falling cntr[1];
  cntr[3] <= ~cntr[3] on falling cntr[2];
  cntr[4] <= ~cntr[4] on falling cntr[3];
  cntr[5] <= ~cntr[5] on falling cntr[4];
  cntr[6] <= ~cntr[6] on falling cntr[5];
  cntr[7] <= ~cntr[7] on falling cntr[6];
end circuits;
end counter8;


// main circuit to test the multiplier 
// checking is manual via  tbmul8.run

signal a[8]; // multiplier
signal b[8]; // multiplicand
signal c[16]; // product
signal clk <= #b1; // clock
signal cntr[8] <= #h00; // 8 bit counter to generate test cases
circuits
  clk <= ~clk after 50ns;  // the clock generator, period is 100ns
  cnt use counter8(cntr, clk);
  a[3:0] <= cntr[3:0];  // some values for a
  a[7:4] <= cntr[3:0];  // some values for a
  b[3:0] <= cntr[7:4];  // some values for b
  b[7:4] <= cntr[7:4];  // some values for b

  mul use bmul8c(a, b, c);

end circuits;