/// <summary>
/// Generates the byte representation of an instruction from a line of assembly code.
/// </summary>
/// <param name="asmLine">The line to parse.</param>
/// <param name="objFile">The object file that will be written to.</param>
/// <param name="currAlignment">The current specified alignment of the file.</param>
public void GenerateCodeForSegment(string fileName, LineData asmLine, BasicObjectFile objFile, int currAlignment)
{
string[] tokens = asmLine.Text.Split(' ', '\t');
string[] fixedTokens = ParserCommon.GetTrimmedTokenArray(tokens).ToArray();
bool foundDataDeclaration = false;
int dataDeclarationIdx = 0;
for (int i = 0; i < fixedTokens.Length && !foundDataDeclaration; ++i)
{
if (ParserCommon.IsDataDeclaration(fixedTokens[i]))
{
foundDataDeclaration = true;
dataDeclarationIdx = i;
}
}
// we found a data declaration; make sure that there's at least one value following it.
if (foundDataDeclaration)
{
if (dataDeclarationIdx + 1 < fixedTokens.Length)
{
// if it is a trivial type, use our precomputed map to get the size.
if (ParserCommon.IsTrivialDataType(fixedTokens[dataDeclarationIdx]))
{
// determine before writing the next data element if we need to add padding.
int paddingSize = ParserCommon.GetNumPaddingBytes(m_NumBytesLaidOut, currAlignment);
int dataSize = ParserCommon.DetermineTrivialDataSize(fixedTokens[dataDeclarationIdx]);
int numElements = ParserCommon.GetArraySize(asmLine.Text, fixedTokens[dataDeclarationIdx]);
if (dataSize > paddingSize)
{
// add as much padding as we need to reach the next alignment boundary.
for (int i = 0; i < paddingSize; ++i)
{
objFile.AddDataElement((byte)0);
m_NumBytesLaidOut += 1;
}
}
int totalReservedSize = dataSize * numElements;
m_NumBytesLaidOut += totalReservedSize;
AddTrivialDataElementsToFile(objFile, dataSize, asmLine.Text, fixedTokens[dataDeclarationIdx]);
}
// see if we can figure out the string length
else if (ParserCommon.IsStringDeclaration(fixedTokens[dataDeclarationIdx]))
{
int paddingSize = ParserCommon.GetNumPaddingBytes(m_NumBytesLaidOut, currAlignment);
// if this is a string declaration, then get the original string data
string dataStr = ParserCommon.GetStringData(asmLine.Text);
int dataSize = ParserCommon.DetermineNonTrivialDataLength(fixedTokens[dataDeclarationIdx], dataStr);
if (dataSize > paddingSize)
{
// add as much padding as we need to reach the next alignment boundary.
for (int i = 0; i < paddingSize; ++i)
{
objFile.AddDataElement((byte)0);
m_NumBytesLaidOut += 1;
}
}
// add the string data to the object file.
AddNonTrivialDataElementToObjectFile(objFile, fixedTokens[dataDeclarationIdx], dataStr);
m_NumBytesLaidOut += dataSize;
}
// otherwise, this must be a .space declaration. just get the size following it.
else
{
int dataSize = ParserCommon.DetermineNonTrivialDataLength(fixedTokens[dataDeclarationIdx], fixedTokens[dataDeclarationIdx + 1]);
int paddingSize = ParserCommon.GetNumPaddingBytes(dataSize, currAlignment);
// fill the space and padding with zeroes.
for (int i = 0; i < dataSize + paddingSize; ++i)
{
objFile.AddDataElement((byte)0);
}
// we expect one token after this word.
// otherwise, it may be garbage that we should detect.
if (fixedTokens.Length > dataDeclarationIdx + 2)
{
throw new AssemblyException(asmLine.LineNum, "Unknown token \"" + fixedTokens[dataDeclarationIdx + 2] + "\" found.");
}
}
}
else
{
throw new AssemblyException(asmLine.LineNum, "Expected data value after token " + fixedTokens[dataDeclarationIdx]);
}
}
// check to see if this is just a label.
// otherwise, it is probably garbage that we should throw.
else if (!ParserCommon.ContainsLabel(asmLine.Text))
{
throw new AssemblyException(asmLine.LineNum, "Unable to ascertain data type from line " + asmLine.Text);
}
}
/// <summary>
/// Parses an unlabeled line to calculate the appropriate address of the next element (if any).
/// </summary>
/// <param name="originalLine">The line data being parsed.</param>
/// <param name="tokens">The string array of space-separated tokens.</param>
/// <param name="alignment">The current alignment</param>
/// <returns>A boolean determining if anything of use was parsed. If this is false,
/// the line should be examined to make sure a symbol was at least parsed. Otherwise,
/// this could indicate that garbage was on the line.</returns>
private bool ParseUnlabeledLine(LineData originalLine, string[] tokens, int alignment)
{
bool foundDataDeclaration = false;
int dataDeclarationIdx = 0;
// scan it for a data size (e.g. .asciiz, .word, etc)
for (int i = 0; i < tokens.Length && !foundDataDeclaration; ++i)
{
if (ParserCommon.IsDataDeclaration(tokens[i]))
{
foundDataDeclaration = true;
dataDeclarationIdx = i;
}
}
// we found a data declaration; make sure that there's at least one value following it.
if (foundDataDeclaration)
{
int dataSize = 0;
if (dataDeclarationIdx + 1 < tokens.Length)
{
// if it is a trivial type, use our precomputed map to get the size.
if (ParserCommon.IsTrivialDataType(tokens[dataDeclarationIdx]))
{
int paddingSize = ParserCommon.GetNumPaddingBytes(m_TotalBytesLaidOut, alignment);
dataSize = ParserCommon.DetermineTrivialDataSize(tokens[dataDeclarationIdx]);
int numElementsToStore = ParserCommon.GetArraySize(originalLine.Text, tokens[dataDeclarationIdx]);
if (dataSize > paddingSize)
{
// add as much padding as we need to reach the next alignment boundary.
for (int i = 0; i < paddingSize; ++i)
{
++m_CurrDataAddress;
++m_TotalBytesLaidOut;
}
}
int reservedSize = numElementsToStore * dataSize;
// need to fixup the address here, since we have committed to placing padding
// here.
if (m_UnresolvedSym != null)
{
m_UnresolvedSym.Address = m_CurrDataAddress;
}
m_CurrDataAddress += reservedSize;
m_TotalBytesLaidOut += reservedSize;
}
// otherwise, we'd expect there to be another token after the data type.
// see if we can figure out the string length
else if (ParserCommon.IsStringDeclaration(tokens[dataDeclarationIdx]))
{
// if this is a string declaration, then get the original string data
string dataStr = ParserCommon.GetStringData(originalLine.Text);
dataSize = ParserCommon.DetermineNonTrivialDataLength(tokens[dataDeclarationIdx], dataStr);
int paddingSize = ParserCommon.GetNumPaddingBytes(m_TotalBytesLaidOut, alignment);
if (dataSize > paddingSize)
{
// add as much padding as we need to reach the next alignment boundary.
for (int i = 0; i < paddingSize; ++i)
{
++m_CurrDataAddress;
++m_TotalBytesLaidOut;
}
}
// need to fixup the address here, since we have committed to placing padding
// here.
if (m_UnresolvedSym != null)
{
m_UnresolvedSym.Address = m_CurrDataAddress;
}
m_CurrDataAddress += dataSize;
m_TotalBytesLaidOut += dataSize;
}
// otherwise, this must be a .space declaration. just get the size following it.
else
{
int paddingSize = ParserCommon.GetNumPaddingBytes(m_TotalBytesLaidOut, alignment);
dataSize = ParserCommon.DetermineNonTrivialDataLength(tokens[dataDeclarationIdx], tokens[dataDeclarationIdx + 1]);
if (dataSize > paddingSize)
{
// add as much padding as we need to reach the next alignment boundary.
for (int i = 0; i < paddingSize; ++i)
{
++m_CurrDataAddress;
++m_TotalBytesLaidOut;
}
}
// need to fixup the address here, since we have committed to placing padding
// here.
// need to really clean this logic up.
if (m_UnresolvedSym != null)
{
m_UnresolvedSym.Address = m_CurrDataAddress;
}
m_CurrDataAddress += dataSize;
m_TotalBytesLaidOut += dataSize;
}
}
else
{
throw new AssemblyException(originalLine.LineNum, "Expected data value after token " + tokens[dataDeclarationIdx]);
}
if (m_UnresolvedSym != null)
{
m_UnresolvedSym.Size = dataSize;
m_UnresolvedSym = null;
}
}
return(foundDataDeclaration);
}
