/*---------------------------------------------------------
 *
 * Multi-fault Fault Simulator (Uniprocessor)
 *
 */

#include<stdlib.h>
#include <iostream.h>
#include<cassert.h>
#include"fault.h"

typedef unsigned char boolean;

int failureNumber;

/* generic one output gate */
/* with initialization to 0 and provision for stuck at faults */
class gate
{
    private:
    int serialNumber;

        public:
    boolean output;
    static int nextSerial;

        gate()
    {
        output = 0;
        serialNumber = nextSerial++;
    }

    boolean &update(const boolean &newval)
    {
        output = newval && ((failureNumber >> serialNumber) & 1);
        return (output);
    }

};

/* two input nand gate */
class nand2:public gate
{
    public:
    boolean &e(const boolean &in1, const boolean &in2)
    {
        return update(!(in1 && in2));
    }
};

int gate::nextSerial = 0;



nand2 s, r, g1, g2, g3, g4, g5, g6, g7, g8, g9, g10, g11, g12,
      g13, g14, g15;

/* a self-evaluating netlist */
boolean &net(boolean in1, boolean in2, boolean in3, boolean in4, boolean in5, boolean in6, boolean in7, boolean in8, boolean reset)
{
// tree of combinational logic followed by an RS flipflop
    (void) g15.e(
                    g13.e(g9.e(g1.e(in1, in2), g2.e(in3, in4)),
                          g10.e(g3.e(in5, in6), g4.e(in7, in8))),
                    g14.e(g11.e(g5.e(in1, in2), g6.e(in3, in4)),
                          g12.e(g7.e(in5, in6), g8.e(in7, in8))));
    (void) r.e(s.e(g15.output, r.output), reset);
    return (r.e(s.e(g15.output, r.output), reset));
}


/* Determine if the test vector detects all faults */
boolean faultSim()
{
    boolean passed = 1;
    boolean thisFaultDetected[testCases];
    boolean answer1, answer2, answer3;

  assert(testCases == 1 << gate::nextSerial);
    thisFaultDetected[testCases] = 1;

    failureNumber = testCases - 1;      // look at fault-free case

    answer1 = net(1, 0, 1, 0, 1, 0, 1, 0, 1);
    answer2 = net(0, 1, 0, 1, 0, 1, 0, 1, 0);
    answer3 = net(1, 0, 1, 0, 1, 1, 1, 0, 1);

    for (failureNumber = 0; failureNumber < testCases - 1; failureNumber++)
      {
          thisFaultDetected[failureNumber] = 1;
// skip remainder of simulation if fault detected on output
          if (answer1 != net(1, 0, 1, 0, 1, 0, 1, 0, 1))
              continue;
          if (answer2 != net(0, 1, 0, 1, 0, 1, 0, 1, 0))
              continue;
          if (answer3 != net(1, 0, 1, 0, 1, 1, 1, 0, 1))
              continue;
          thisFaultDetected[failureNumber] = 0;
          passed = 0;
      }
    return (passed);
}