private static void ParseInstruction()
{
if (currentLexem == Lexems.Identificator)
{
Identifier identifier = Translation.NameTable.SearchByName(currentName);
if (!identifier.Equals(new Identifier()))
{
ParseInstructionAssignment();
CodeGens.AddInstructions("pop ax");
CodeGens.AddInstructions("mov " + identifier.name + ",ax");
}
else
{
Error("необъявленная переменная " + currentName);
}
}
else if (currentLexem == Lexems.Print)
{
ParsePrintInstruction();
}
else if (currentLexem == Lexems.If)
{
ParseBranching();
}
else if (currentLexem == Lexems.Do)
{
ParseLoop();
}
}
public static void ParseLoop()
{
ParseNextLexem();
CodeGens.AddLabel();
string TopLabel = CodeGens.GetCurrentLabel();
CodeGens.AddLabel();
string LowLabel = CodeGens.GetCurrentLabel();
CodeGens.AddLabel();
string Thirdlabel = CodeGens.GetCurrentLabel();
currentLabel = Thirdlabel;
CodeGens.AddInstructions("jmp " + LowLabel);
CodeGens.AddInstructions(TopLabel + ":");
//ParseExpression();
ParseInstructionsSequence();
//
CheckSyntax(Lexems.While);
ParseNextLexem();
CodeGens.AddInstructions(LowLabel + ":");
ParseExpression();
CodeGens.AddInstructions("jmp " + TopLabel);
CodeGens.AddInstructions(Thirdlabel + ":");
//{
// ParseNextLexem();
// CodeGens.AddLabel();
// string label = CodeGens.GetCurrentLabel();
// CodeGens.AddInstructions(label + ":");
// ParseInstructionsSequence();
// CheckLexems(Lexems.While);
// ParseExpression();
//}
}
public static void ParseBranching()
{
// //CheckLexems(Lexems.If);
// ParseNextLexem();
// ParseExpression();
// CodeGens.AddLabel();
// string lowlable=CodeGens.GetCurrentLabel();
// currentLabel=lowlable;
// CheckLexems(Lexems.Then);
// ParseInstructionsSequence();
// while (currentLexem == Lexems.ElseIf)
// {
// ParseExpression();
// CheckLexems(Lexems.Then);
// ParseInstructionsSequence();
// }
// if (currentLexem == Lexems.Else)
// {
// ParseNextLexem();
// ParseInstructionsSequence();
// }
// CheckLexems(Lexems.EndIf);
ParseNextLexem();
CodeGens.AddLabel();
string lowestLabel = CodeGens.GetCurrentLabel();
currentLabel = lowestLabel;
CodeGens.AddLabel();
string exitLabel = CodeGens.GetCurrentLabel();
ParseExpression();
CheckSyntax(Lexems.Then);
ParseInstructionsSequence();
CodeGens.AddInstructions("jmp " + exitLabel);
while (currentLexem == Lexems.ElseIf)
{
CodeGens.AddInstructions(lowestLabel + ":");
CodeGens.AddLabel();
lowestLabel = CodeGens.GetCurrentLabel();
currentLabel = lowestLabel;
ParseNextLexem();
ParseExpression();
CheckSyntax(Lexems.Then);
ParseInstructionsSequence();
CodeGens.AddInstructions("jmp " + exitLabel);
}
if (currentLexem == Lexems.Else)
{
CodeGens.AddInstructions(lowestLabel + ":");
// ParseNextLexem();
ParseInstructionsSequence();
}
CheckSyntax(Lexems.EndIf);
CodeGens.AddInstructions(exitLabel + ":");
}
public static TType ParseSubExpression()
{
Identifier X;
TType T = TType.None;
if (currentLexem == Lexems.Identificator)
{
X = NameTable.SearchByName(currentName);
if (!X.Equals(new Identifier()) & X.cat == TCat.Var)
{
CodeGens.AddInstructions("mov ax," + currentName);
CodeGens.AddInstructions("push ax");
ParseNextLexem();
return(X.type);
}
else
{
Error("unknown parameter");
}
return(T);
}
else if (currentLexem == Lexems.Number)
{
CodeGens.AddInstructions("mov ax," + currentName);
CodeGens.AddInstructions("push ax");
ParseNextLexem();
return(TType.Int);
}
else if (currentLexem == Lexems.LesfBracket)
{
ParseNextLexem();
T = ParseExpression();
if (currentLexem != Lexems.RightBracket)
{
Error("Unknown " + currentLexem.ToString() + " '" + currentName + "'");
}
else
{
ParseNextLexem();
}
}
else
{
Error("Unknwon parameter");
}
return(T);
}
private static TType ParseExpression()
{
TType T = ParseAdditionsAndSubstractions();
if (currentLexem == Lexems.NotEqual || currentLexem == Lexems.Less || currentLexem == Lexems.LessOrEqual ||
currentLexem == Lexems.Equal || currentLexem == Lexems.Greater || currentLexem == Lexems.GreaterOrEqual
)
{
string transition = "";
switch (currentLexem)
{
case Lexems.Equal:
transition = "jne";
break;
case Lexems.NotEqual:
transition = "je";
break;
case Lexems.Greater:
transition = "jle";
break;
case Lexems.GreaterOrEqual:
transition = "jl";
break;
case Lexems.Less:
transition = "jge";
break;
case Lexems.LessOrEqual:
transition = "jg";
break;
}
ParseNextLexem();
ParseAdditionsAndSubstractions();
CodeGens.AddInstructions("pop ax");
CodeGens.AddInstructions("pop bx");
CodeGens.AddInstructions("cmp bx, ax");
CodeGens.AddInstructions(transition + " " + currentLabel);
currentLabel = "";
T = TType.Bool;
}
return(T);
}
private static TType ParseAdditionsAndSubstractions()
{
TType t;
Lexems operator_;
if (currentLexem == Lexems.Plus || currentLexem == Lexems.Minus)
{
operator_ = currentLexem;
ParseNextLexem();
t = ParseMultiplicationAndDivision();
}
else
{
t = ParseMultiplicationAndDivision();
}
if (currentLexem == Lexems.Plus || currentLexem == Lexems.Minus)
{
do
{
operator_ = currentLexem;
ParseNextLexem();
t = ParseMultiplicationAndDivision();
switch (operator_)
{
case Lexems.Plus:
CodeGens.AddInstructions("pop bx");
CodeGens.AddInstructions("pop ax");
CodeGens.AddInstructions("add ax,bx");
CodeGens.AddInstructions("push ax");
break;
case Lexems.Minus:
CodeGens.AddInstructions("pop bx");
CodeGens.AddInstructions("pop ax");
CodeGens.AddInstructions("sub ax,bx");
CodeGens.AddInstructions("push ax");
break;
}
} while (currentLexem == Lexems.Plus || currentLexem == Lexems.Minus);
}
return(t);
}
private static void ParsePrintInstruction()
{
// CheckSyntax(Lexems.Identificator);
ParseNextLexem();
if (currentLexem == Lexems.Identificator)
{
Identifier X = NameTable.SearchByName(currentName);
if (!X.Equals(new Identifier()))
{
CodeGens.AddInstructions("push ax");
CodeGens.AddInstructions("mov ax," + currentName);
CodeGens.AddInstructions("CALL PRINT");
CodeGens.AddInstructions("pop ax");
ParseNextLexem();
}
}
else
{
Error("unkown parameter " + currentName);
}
}
private static TType ParseMultiplicationAndDivision()
{
Lexems operator_;
TType t = ParseSubExpression();
if (currentLexem == Lexems.Multiplication || currentLexem == Lexems.Division)
{
do
{
operator_ = currentLexem;
ParseNextLexem();
t = ParseSubExpression();
switch (operator_)
{
case Lexems.Multiplication:
CodeGens.AddInstructions("pop bx");
CodeGens.AddInstructions("pop ax");
CodeGens.AddInstructions("mul bx");
CodeGens.AddInstructions("push ax");
break;
case Lexems.Division:
CodeGens.AddInstructions("pop bx");
CodeGens.AddInstructions("pop ax");
CodeGens.AddInstructions("cwd");
CodeGens.AddInstructions("div bl");
CodeGens.AddInstructions("push ax");
break;
default:
break;
}
} while (currentLexem == Lexems.Multiplication || currentLexem == Lexems.Division);
}
return(t);
}
