private void DereferenceToIndex()
{
for (int index = 0; index < (m_middleCodeList.Count - 1); ++index)
{
MiddleCode thisCode = m_middleCodeList[index],
nextCode = m_middleCodeList[index + 1];
// *(a + 3) <=> a[3] <=> *(3 + a) <=> 3[a]
if ((thisCode.Operator == MiddleOperator.Add) &&
(nextCode.Operator == MiddleOperator.Dereference) &&
(thisCode[0] == nextCode[1]))
{
Symbol leftSymbol = (Symbol)thisCode[1],
rightSymbol = (Symbol)thisCode[2];
if (leftSymbol.Value is BigInteger)
{
Symbol resultSymbol = (Symbol)nextCode[0];
resultSymbol.AddressSymbol = rightSymbol;
resultSymbol.AddressOffset = ((int)((BigInteger)leftSymbol.Value));
thisCode.Clear();
}
else if (rightSymbol.Value is BigInteger)
{
Symbol resultSymbol = (Symbol)nextCode[0];
resultSymbol.AddressSymbol = leftSymbol;
resultSymbol.AddressOffset = ((int)((BigInteger)rightSymbol.Value));
thisCode.Clear();
}
}
// *(a - 3) <=> a[-3]
else if ((thisCode.Operator == MiddleOperator.Subtract) &&
(nextCode.Operator == MiddleOperator.Dereference) &&
(thisCode[0] == nextCode[1]))
{
Symbol leftSymbol = (Symbol)thisCode[1],
rightSymbol = (Symbol)thisCode[2];
if (rightSymbol.Value is BigInteger)
{
Symbol resultSymbol = (Symbol)nextCode[0];
resultSymbol.AddressSymbol = leftSymbol;
resultSymbol.AddressOffset = -((int)((BigInteger)rightSymbol.Value));
thisCode.Clear();
}
}
}
}
// Top x + Pop => Pop x
// top x
// pop
// pop x
public void MergeTopPopEmptyToPop()
{
for (int index = 0; index < (m_middleCodeList.Count - 1); ++index)
{
MiddleCode thisCode = m_middleCodeList[index],
nextCode = m_middleCodeList[index + 1];
if ((thisCode.Operator == MiddleOperator.TopFloat) &&
(nextCode.Operator == MiddleOperator.PopEmpty))
{
thisCode.Operator = MiddleOperator.PopFloat;
nextCode.Clear();
m_update = true;
}
}
}
// t = a
// b = t
// b = a
private void MergeDoubleAssign()
{
for (int index = 0; index < (m_middleCodeList.Count - 1); ++index)
{
MiddleCode thisCode = m_middleCodeList[index],
nextCode = m_middleCodeList[index + 1];
if ((thisCode.Operator == MiddleOperator.Assign) &&
(nextCode.Operator == MiddleOperator.Assign) &&
thisCode[0] == nextCode[1])
{
thisCode[0] = nextCode[0];
nextCode.Clear();
m_update = true;
}
}
}
// Push x + Pop => empty
// push x
// pop
// empty
public void RemovePushPop()
{
for (int index = 0; index < (m_middleCodeList.Count - 1); ++index)
{
MiddleCode thisCode = m_middleCodeList[index],
nextCode = m_middleCodeList[index + 1];
if ((thisCode.Operator == MiddleOperator.PushFloat) &&
((nextCode.Operator == MiddleOperator.PopEmpty) ||
((nextCode.Operator == MiddleOperator.PopFloat) &&
(thisCode[0] == nextCode[0]))))
{
thisCode.Clear();
nextCode.Clear();
m_update = true;
}
}
}
// --------------------------------------------------------------------------
// 1. goto 2
// 2. ...
private void ClearGotoNextStatements()
{
for (int index = 0; index < (m_middleCodeList.Count - 1); ++index)
{
MiddleCode middleCode = m_middleCodeList[index];
if (middleCode.IsRelationCarryOrGoto())
{
int target = (int)middleCode[0];
if (target == (index + 1))
{
middleCode.Clear();
m_update = true;
}
}
}
}
// t = b + c
// a = t
// a = b + c
private void MergeBinary()
{
for (int index = 0; index < (m_middleCodeList.Count - 1); ++index)
{
MiddleCode thisCode = m_middleCodeList[index],
nextCode = m_middleCodeList[index + 1];
if ((/*thisCode.IsUnary() ||*/ thisCode.IsBinary()) &&
(nextCode.Operator == MiddleOperator.Assign) &&
((Symbol)thisCode[0]).IsTemporary() &&
(thisCode[0] == nextCode[1]))
{
thisCode[0] = nextCode[0];
nextCode.Clear();
m_update = true;
}
}
}
private void ClearDoubleRelationStatements()
{
for (int index = 0; index < (m_middleCodeList.Count - 1); ++index)
{
MiddleCode thisCode = m_middleCodeList[index],
nextCode = m_middleCodeList[index + 1];
if ((thisCode.IsRelation() || thisCode.IsCarry()) &&
nextCode.IsGoto())
{
int target1 = (int)thisCode[0],
target2 = (int)nextCode[0];
if (target1 == (index + 2))
{
MiddleOperator operator1 = thisCode.Operator;
thisCode.Operator = m_inverseMap[operator1];
thisCode[0] = target2;
nextCode.Clear();
m_update = true;
}
}
}
}