public IntermediateCode(IntermediateCode icode = null)
{
if (icode == null)
{
m_formatter = new BinaryFormatter();
} else
{
m_formatter = new BinaryFormatter(icode.m_formatter.Stream);
}
}
public void PopFrame(SymtabNode pRoutineId, ref IntermediateCode pIcode)
{
TFrameHeader pHeader = (TFrameHeader)stack[pFrameBase];
//--Don't do anything if it's the bottommost stack frame.
if (pFrameBase != 0)
{
//--Return to the caller's intermediate code.
pIcode = pHeader.returnAddress.icode;
pIcode.GoTo((int)pHeader.returnAddress.location);
//--Cut the stack back. Leave a function value on top.
tos = pFrameBase;
//if (pRoutineId.defn.how != TDefnCode.dcFunction) --tos;
// pFrameBase = (TStackItem)pHeader.dynamicLink.Value;
}
}
static void Main(string[] args)
{
// string source = @"
//PROGRAM fibonacci (output);
//
//VAR
// number : integer;
//
//FUNCTION fib (n : integer) : integer;
//
// BEGIN
// IF n <= 1 THEN fib := n
// ELSE fib := fib(n - 2) + fib(n - 1)
// END;
//
//BEGIN
// FOR number:= 0 TO 16 DO BEGIN
// writeln('number = ', number:2,
// ' fibonacci = ', fib(number):4);
// END;
//END.";
string simpleSource = @"identifier := 123;
somestring := 'abc';
updatevalue := identifier + 5;
output := updatevalue
.";
string testNewtons
=
@"{Square roots by Newton's algorithm.}
number := input;
root := number;
root := (number/root + root)/2; output := root;
root := (number/root + root)/2; output := root;
root := (number/root + root)/2; output := root;
root := (number/root + root)/2; output := root;
root := (number/root + root)/2; output := root;
root := (number/root + root)/2; output := root;
root := (number/root + root)/2; output := root;
root := (number/root + root)/2; output := root;
root := (number/root + root)/2; output := root;
.";
string source;
using (StreamReader reader = new StreamReader(File.OpenRead("source.pas")))
{
source = reader.ReadToEnd();
}
SharedProperties.globalSymtab = Symtab.CreateTable();
TextBuffer buffer = new TextBuffer(File.OpenRead("source.pas"));
IntermediateCode icode = new IntermediateCode();
SymtabStack symbolTableStack = new SymtabStack(SharedProperties.globalSymtab);
StagingParser parser = new StagingParser(buffer, icode, symbolTableStack);
parser.Error += new EventHandler<ErrorEventArgs>(parser_Error);
parser.Parse();
Console.WriteLine();
// -- print the parsers summary
string message = string.Format("{0} source lines", buffer.LineNumber - 1);
int spaceCount = (Console.WindowWidth - message.Length) / 2;
Console.WriteLine(string.Format("{0," + spaceCount + "}", message));
message = string.Format("{0} syntax errors.", buffer.ErrorCount);
spaceCount = (Console.WindowWidth - message.Length) / 2;
Console.WriteLine(string.Format("{0," + spaceCount + "}", message));
Console.WriteLine();
TExecutor executer = new TExecutor(icode);
executer.Error += new EventHandler<RuntimeErrorArgs>(executer_Error);
executer.Go();
if (executer.ErrorCount > 0)
{
Console.WriteLine("Successful completion. {0} statements executed.", executer.StatementCount);
}
else
{
Console.WriteLine("Completed with {0} errors.", executer.ErrorCount);
}
Console.ReadKey();
}
protected TTokenCode token; // code of current token
#endregion Fields
#region Constructors
public TBackend(IntermediateCode icode)
{
this.icode = icode;
}
public TExecutor(IntermediateCode icode)
: base(icode)
{
pInputNode = SharedProperties.globalSymtab.Search("input");
pOutputNode = SharedProperties.globalSymtab.Search("output");
}
private TTokenCode token; // code of current token
#endregion Fields
#region Constructors
public StagingParser(TextBuffer buffer, IntermediateCode icode, SymtabStack symbolStack)
{
this.buffer = buffer;
this.icode = icode;
this.symtabStack = symbolStack;
pScanner = new TextScanner(this.buffer);
// -- Enter the special "input" and "output" variable identifiers
// -- into the symbol table.
EnterLocal("input");
EnterLocal("output");
}
public object PushFrameHeader(int oldLevel, int newLevel,
IntermediateCode pIcode)
{
TFrameHeader pHeader = (TFrameHeader)stack[pFrameBase];
object pNewFrameBase = stack[tos + 1]; // point to item just above
// current TOS item
Push(0); // function return value (placeholder)
//--Compute the static link.
if (newLevel == oldLevel + 1)
{
//--Callee nested within caller:
//--Push address of caller's stack frame.
Push(pHeader);
}
else if (newLevel == oldLevel)
{
//--Callee at same level as caller:
//--Push address of common parent's stack frame.
Push(pHeader.staticLink);
}
else /* newLevel < oldLevel */
{
//--Callee nested less deeply than caller:
//--Push address of nearest commmon ancestor's stack frame.
int delta = oldLevel - newLevel;
while (delta-- >= 0)
{
pHeader = (TFrameHeader)pHeader.staticLink;
}
Push(pHeader);
}
Push(pFrameBase); // dynamic link
Push(pIcode); // return address icode pointer
Push(0); // return address icode location (placeholder)
return pNewFrameBase;
}