public static int Evaluate(Expression exp, int var)
{
if (exp is ConstantExpression)
{
ConstantExpression tExp = exp as ConstantExpression;
return((int)(exp as ConstantExpression).Value);
}
else if (exp is VariableExpression)
{
return(var);
}
else if (exp is AddExpression)
{
AddExpression nExp = (AddExpression)exp;
return(Evaluate(nExp.OperandA, var) + Evaluate(nExp.OperandB, var));
}
else if (exp is SubExpression)
{
SubExpression nExp = (SubExpression)exp;
return(Evaluate(nExp.OperandA, var) - Evaluate(nExp.OperandB, var));
}
else if (exp is MulExpression)
{
MulExpression nExp = (MulExpression)exp;
return(Evaluate(nExp.OperandA, var) * Evaluate(nExp.OperandB, var));
}
else if (exp is DivExpression)
{
DivExpression nExp = (DivExpression)exp;
return(Evaluate(nExp.OperandA, var) / Evaluate(nExp.OperandB, var));
}
else if (exp is NegExpression)
{
NegExpression nExp = (NegExpression)exp;
return(-Evaluate(nExp.Value, var));
}
else if (exp is InvExpression)
{
InvExpression nExp = (InvExpression)exp;
return(~Evaluate(nExp.Value, var));
}
else if (exp is XorExpression)
{
XorExpression nExp = (XorExpression)exp;
return(Evaluate(nExp.OperandA, var) ^ Evaluate(nExp.OperandB, var));
}
throw new NotSupportedException();
}
public override void VisitPostOrder(Expression exp)
{
x86Register reg = GetFreeRegister(exp);
if (exp is ConstantExpression)
{
insts.Add(new x86Instruction()
{
OpCode = x86OpCode.MOV,
Operands = new Ix86Operand[]
{
new x86RegisterOperand()
{
Register = reg
},
new x86ImmediateOperand()
{
Immediate = (exp as ConstantExpression).Value
}
}
});
SetRegister(exp, reg);
}
else if (exp is VariableExpression)
{
insts.AddRange(args(reg));
SetRegister(exp, reg);
}
else if (exp is AddExpression)
{
AddExpression _exp = exp as AddExpression;
insts.Add(new x86Instruction()
{
OpCode = x86OpCode.ADD,
Operands = new Ix86Operand[]
{
new x86RegisterOperand()
{
Register = GetRegister(_exp.OperandA)
},
new x86RegisterOperand()
{
Register = GetRegister(_exp.OperandB)
}
}
});
SetRegister(exp, GetRegister(_exp.OperandA));
ReleaseRegister(_exp.OperandB);
}
else if (exp is SubExpression)
{
SubExpression _exp = exp as SubExpression;
insts.Add(new x86Instruction()
{
OpCode = x86OpCode.SUB,
Operands = new Ix86Operand[]
{
new x86RegisterOperand()
{
Register = GetRegister(_exp.OperandA)
},
new x86RegisterOperand()
{
Register = GetRegister(_exp.OperandB)
}
}
});
SetRegister(exp, GetRegister(_exp.OperandA));
ReleaseRegister(_exp.OperandB);
}
else if (exp is MulExpression)
{
throw new NotSupportedException();
}
else if (exp is DivExpression)
{
throw new NotSupportedException();
}
else if (exp is NegExpression)
{
NegExpression _exp = exp as NegExpression;
insts.Add(new x86Instruction()
{
OpCode = x86OpCode.NEG,
Operands = new Ix86Operand[]
{
new x86RegisterOperand()
{
Register = GetRegister(_exp.Value)
}
}
});
SetRegister(exp, GetRegister(_exp.Value));
}
else if (exp is InvExpression)
{
InvExpression _exp = exp as InvExpression;
insts.Add(new x86Instruction()
{
OpCode = x86OpCode.NOT,
Operands = new Ix86Operand[]
{
new x86RegisterOperand()
{
Register = GetRegister(_exp.Value)
}
}
});
SetRegister(exp, GetRegister(_exp.Value));
}
else if (exp is XorExpression)
{
XorExpression _exp = exp as XorExpression;
insts.Add(new x86Instruction()
{
OpCode = x86OpCode.XOR,
Operands = new Ix86Operand[]
{
new x86RegisterOperand()
{
Register = GetRegister(_exp.OperandA)
},
new x86RegisterOperand()
{
Register = GetRegister(_exp.OperandB)
}
}
});
SetRegister(exp, GetRegister(_exp.OperandA));
ReleaseRegister(_exp.OperandB);
}
}