Avoid Module creation for Constant Gate scenarios #481
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lib/src/signals/logic.dart
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| Logic operator ~() => NotGate(this).out; | ||
| Logic operator ~() { | ||
| if (this is Const) { | ||
| if (value.isValid) { |
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I think we can rely on the operators within LogicValue for this? i.e. something like Const(~this.value)?
lib/src/signals/logic.dart
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| return this; | ||
| } | ||
| } else { | ||
| return Const(LogicValue.x, width: width); |
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This isn't quite right, consider 11x11 & 11111 == 11x11
If we just cover the cases of all 0's and all 1's that's probably enough and let the rest fall through to the and gate?
lib/src/signals/logic.dart
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| other.value == LogicValue.of(0, width: width)) { | ||
| return Const(LogicValue.of(0, width: width)); | ||
| } else if (value == LogicValue.filled(width, LogicValue.one)) { | ||
| return other; |
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What if other is Const and this is not Const but has a value of all 1s currently? Need to be cautious to only consider the value if it's a Const.
lib/src/signals/logic.dart
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| /// Logical bitwise AND. | ||
| Logic operator &(Logic other) => And2Gate(this, other).out; | ||
| Logic operator &(Logic other) { | ||
| if (this is Const && |
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I think this can be made a little more general? If either one is a Const, then you can do something special:
- If one of the two is constant all 1's, then return the other
- If one of the two is constant all 0's, then return 0
The current logic only covers if both are const.
You could remove some duplication in the implementation by making local variables to point to "the constant one" and "the other one", so you don't need to consider it both ways for all cases.
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| /// Logical bitwise OR. | ||
| Logic operator |(Logic other) => Or2Gate(this, other).out; | ||
| Logic operator |(Logic other) { |
test/gate_test.dart
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| @@ -353,6 +353,115 @@ void main() { | |||
| }); | |||
| }); | |||
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| group('Const input Gate test', () { | |||
| test('NotGate single bit Constant input', () async { | |||
| final a = Logic(); | |||
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naming the variables could be helpful for understanding the intent of the test, e.g. normalLogic, const0, etc.
test/gate_test.dart
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| final d = Const(LogicValue.one, width: 1); | ||
| a.put(LogicValue.one); | ||
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| expect(a & b, isA<Logic>()); |
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anything & 0 should be a constant 0
| expect((a | c).value, equals(LogicValue.one)); | ||
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| expect(a | d, isA<Logic>()); | ||
| expect((a | d).value, equals(LogicValue.one)); |
Description & Motivation
#429
Related Issue(s)
#429
Testing
Added test cases to check if the result of '&', '|' and '~' operations are as expected for constant input scenarios.
Backwards-compatibility
No.
Documentation
No.