Avoid Module creation for Constant Gate scenarios

lib/src/signals/logic.dart

@@ -383,13 +383,59 @@ class Logic {
   void operator <=(Logic other) => gets(other);
 
   /// Logical bitwise NOT.
-  Logic operator ~() => NotGate(this).out;
+  Logic operator ~() => this is Const ? Const(~value) : NotGate(this).out;
 
   /// Logical bitwise AND.
-  Logic operator &(Logic other) => And2Gate(this, other).out;
+  Logic operator &(Logic other) {
+    if (this is Const && other is Const) {
+      return Const((this as Const).value & other.value);
+    }
+    Const? constOperand;
+    Logic? otherOperand;
+
+    if (this is Const && value.isValid) {
+      constOperand = Const(this);
+    } else if (other is Const && other.value.isValid) {
+      constOperand = other;
+      otherOperand = this;
+    }
+
+    if (constOperand != null) {
+      if (constOperand.value == LogicValue.filled(width, LogicValue.zero)) {
+        return Const(LogicValue.filled(width, LogicValue.zero));
+      } else if (constOperand.value ==
+          LogicValue.filled(width, LogicValue.one)) {
+        return otherOperand!;
+      }
+    }
+    return And2Gate(this, other).out;
+  }
 
   /// Logical bitwise OR.
-  Logic operator |(Logic other) => Or2Gate(this, other).out;
+  Logic operator |(Logic other) {
+    if (this is Const && other is Const) {
+      return Const((this as Const).value | other.value);
+    }
+    Const? constOperand;
+    Logic? otherOperand;
+
+    if (this is Const && value.isValid) {
+      constOperand = Const(this);
+    } else if (other is Const && other.value.isValid) {
+      constOperand = other;
+      otherOperand = this;
+    }
+
+    if (constOperand != null) {
+      if (constOperand.value == LogicValue.filled(width, LogicValue.one)) {
+        return Const(LogicValue.filled(width, LogicValue.one));
+      } else if (constOperand.value ==
+          LogicValue.filled(width, LogicValue.zero)) {
+        return otherOperand!;
+      }
+    }
+    return Or2Gate(this, other).out;
+  }
 
   /// Logical bitwise XOR.
   Logic operator ^(Logic other) => Xor2Gate(this, other).out;

test/gate_test.dart

@@ -353,6 +353,109 @@ void main() {
     });
   });
 
+  group('Const input Gate test', () {
+    test('NotGate single bit Constant input', () async {
+      final normalLogic = Logic();
+      final const0 = Const(LogicValue.zero, width: 1);
+      final constX = Const(LogicValue.x, width: 1);
+      final const1 = Const(LogicValue.one, width: 1);
+      normalLogic.put(LogicValue.one);
+
+      expect(~const0, isA<Const>());
+      expect((~const0).value, equals(LogicValue.one));
+
+      expect(~constX, isA<Const>());
+      expect((~constX).value, equals(LogicValue.x));
+
+      expect(~const1, isA<Const>());
+      expect((~const1).value, equals(LogicValue.zero));
+    });
+
+    test('NotGate Multi bit Constant input', () async {
+      final const1 = Const(bin('1111'), width: 4);
+      final const4 = Const(bin('0100'), width: 4);
+
+      expect(~const1, isA<Const>());
+      expect((~const1).value, equals(LogicValue.of(LogicValue.zero, width: 4)));
+
+      expect(~const4, isA<Logic>());
+      expect((~const4).value, equals(LogicValue.of(11, width: 4)));
+    });
+
+    test('And2Gate Single bit Constant input', () async {
+      final normalLogic = Logic();
+      final const0 = Const(LogicValue.zero);
+      final logicX = Logic();
+      final const1 = Const(LogicValue.one);
+      normalLogic.put(LogicValue.one);
+      logicX.put(LogicValue.x);
+
+      expect(normalLogic & const0, isA<Const>());
+      expect((normalLogic & const0).value, equals(LogicValue.zero));
+      expect(logicX & const0, isA<Const>());
+      expect((logicX & const0).value, equals(LogicValue.zero));
+      expect(normalLogic & const1, isA<Logic>());
+      expect((normalLogic & const1).value, equals(normalLogic.value));
+      expect(normalLogic & logicX, isA<Logic>());
+      expect((normalLogic & logicX).value, equals(LogicValue.x));
+      expect(const0 & const1, isA<Const>());
+    });
+
+    test('And2Gate Multi bit Constant input', () async {
+      final const1 = Const(bin('1111'), width: 4);
+      final const4 = Const(bin('0100'), width: 4);
+      final logic0 = Logic(width: 4)..put(LogicValue.zero);
+      final logic1 = Logic(width: 4)..put(LogicValue.one);
+      final logicX = Logic(width: 4)..put(LogicValue.x);
+
+      expect(const1 & const4, isA<Const>());
+      expect((const1 & const4).value, equals(LogicValue.of('0100', width: 4)));
+
+      expect(logic0 & const1, isA<Logic>());
+      expect((logic0 & const1).value, equals(LogicValue.of('0000', width: 4)));
+
+      expect(logic1 & const1, isA<Logic>());
+      expect((logic1 & const1).value, equals(LogicValue.of('0001', width: 4)));
+
+      expect(logicX & const1, isA<Logic>());
+      expect((logicX & const1).value, equals(LogicValue.of('xxxx', width: 4)));
+    });
+
+    test('OR2Gate Single bit Constant input', () async {
+      final a = Logic();
+      final b = Const(LogicValue.zero, width: 1);
+      final c = Const(LogicValue.x, width: 1);
+      final d = Const(LogicValue.one, width: 1);
+      final z = Const('11111', width: 5);
+      final y = Const(LogicValue.of('11x01', width: 5));
+      a.put(LogicValue.one);
+
+      expect(a | b, isA<Logic>());
+      expect((a | b).value, equals(a.value));
+
+      expect(a | c, isA<Logic>());
+      expect((a | c).value, equals(LogicValue.one));
+
+      expect(a | d, isA<Logic>());
+      expect((a | d).value, equals(LogicValue.one));
+
+      expect(y | z, isA<Logic>());
+      expect((y | z).value, equals(LogicValue.of('11111', width: 5)));
+    });
+
+    test('OR2Gate Multi bit Constant input', () async {
+      final a = Const(LogicValue.of(LogicValue.zero, width: 4));
+      final b = Const(bin('1111'), width: 4);
+      final c = Const(bin('0100'), width: 4);
+
+      expect(a | c, isA<Logic>());
+      expect((a | c).value, equals(c.value));
+
+      expect(b | c, isA<Const>());
+      expect((b | c).value, equals(LogicValue.filled(4, LogicValue.one)));
+    });
+  });
+
   group('simcompare', () {
     test('NotGate single bit', () async {
       final gtm = GateTestModule(Logic(), Logic());