public static bool SimplifyOperands(ISignalSet signals)
{
if (signals.Count < 2)
{
return(false);
}
bool changed = false;
Signal radix = signals[0];
if (Std.IsConstantAdditiveIdentity(radix) && Std.IsConstant(signals[1]))
{
if (Std.IsAlwaysNegative(signals[1]))
{
signals.Clear();
signals.Add(UndefinedSymbol.Constant);
return(true);
}
signals.Clear();
signals.Add(radix);
return(true);
}
if (Std.IsConstantMultiplicativeIdentity(radix))
{
signals.Clear();
signals.Add(radix);
return(true);
}
// Evaluate all but the first two operands -> nonnegative integers
IntegerValue value = null;
for (int i = signals.Count - 1; i > 1; i--)
{
Signal s = signals[i];
if (!Std.IsConstantNonnegativeInteger(s))
{
if (changed)
{
if (!value.IsMultiplicativeIdentity)
{
signals.Add(Std.DefineConstant(value));
}
return(true);
}
return(false);
}
signals.RemoveAt(i);
value = ValueConverter <IntegerValue> .ConvertFrom(s.Value).PositiveIntegerPower((int)value.Value);
changed = true;
}
// Evaluate the second operand -> integer (can also be negative)
Signal exponent = signals[1];
if (!Std.IsConstantInteger(exponent))
{
if (changed)
{
if (!value.IsMultiplicativeIdentity)
{
signals.Add(Std.DefineConstant(value));
}
return(true);
}
return(false);
}
IntegerValue exponentValue = ValueConverter <IntegerValue> .ConvertFrom(exponent.Value);
if (changed)
{
exponentValue = exponentValue.PositiveIntegerPower((int)value.Value);
}
// Special case: first operand is a power
if (radix.IsDrivenByPortEntity(PowerArchitectures.EntityIdentifier) &&
radix.DrivenByPort.InputSignalCount == 2 &&
Std.IsConstantInteger(radix.DrivenByPort.InputSignals[1]))
{
exponentValue = exponentValue.Multiply(ValueConverter <IntegerValue> .ConvertFrom(radix.DrivenByPort.InputSignals[1].Value));
signals[0] = radix = radix.DrivenByPort.InputSignals[0];
changed = true;
}
// Evaluate the first operand
if (!Std.IsConstantComplex(radix))
{
if (changed)
{
if (!exponentValue.IsMultiplicativeIdentity)
{
signals[1] = Std.DefineConstant(exponentValue);
}
else
{
signals.RemoveAt(1);
}
return(true);
}
return(false);
}
IAccumulator acc = Accumulator <IntegerValue, RationalValue> .Create(radix.Value);
acc = acc.IntegerPower((int)exponentValue.Value);
signals.Clear();
signals.Add(Std.DefineConstant(acc.Value));
return(true);
}
