private void detectSymbolsAndBaseAddresses() throws IOException {
Hashtable<String, Integer> moduleSymbols = new Hashtable<String, Integer>();
int nd = parseNumber();
for (int i = 1; i <= nd; i++) {
String symbol = parseWord();
if (SymbolTable.defines(symbol)) {
String error = "Error: This variable is multiply defined; first value used.";
SymbolTable.getInstance().getErrors().put(symbol, error);
} else {
moduleSymbols.put(symbol, parseNumber() + this.baseAddress);
SymbolTable.getInstance().put(symbol, moduleSymbols.get(symbol));
}
}
skipUseList();
int moduleSize = parseNumber();
skipProgram(moduleSize);
MemoryMap.createProgramModule(this.baseAddress, moduleSymbols);
this.baseAddress += moduleSize;
skipWhiteSpace();
}
/*
* Function : parseInstruction
* Description : Parses the IType instructions without displacements.
*/
public static ITypeImmediate parseInstruction(String instruction, int address) {
ITypeImmediate instruct = new ITypeImmediate();
// set the icode
instruct.icode = IMap.get(Instruction.getIcodeName(instruction));
// grab the string from the registers.java class that we will use to match registers
Pattern registerPattern = Pattern.compile(Registers.registerString());
Matcher registerMatcher = registerPattern.matcher(instruction);
// match the first register if there is one
if (registerMatcher.find()) {
instruct.rd = Registers.registerValue(registerMatcher.group(0));
// I clear off the bits we've already read
instruction = instruction.substring(registerMatcher.end(0));
}
// match the second register if we can
if (registerMatcher.find()) {
instruct.r1 = Registers.registerValue(registerMatcher.group(0));
}
// This regex attempts to match a label name. The [^\\s\\d] means not a space or digit character
// This ensures that the label is infact a valid label and does not start with a number.
Pattern symbolPattern = Pattern.compile("\\b([^\\d\\s][^\\s]*)\\b$");
Matcher symbolMatcher = symbolPattern.matcher(instruction);
Pattern literalPattern = Pattern.compile("\\b(0x)?\\d+\\b");
Matcher literalMatcher = literalPattern.matcher(instruction);
if (symbolMatcher.find()) {
SymbolTable symbolTable = SymbolTable.getInstance();
instruct.immediateValue = symbolTable.getSymbol(symbolMatcher.group(0).replace(" ", ""));
if (instruct.icode == BEQZ || instruct.icode == BNEZ) {
instruct.r1 = instruct.rd;
instruct.rd = 0;
instruct.immediateValue = instruct.immediateValue - (address + 4);
}
} else if (literalMatcher.find()) {
instruct.immediateValue = Tools.processNumber(literalMatcher.group(0).replace(" ", ""));
} else {
instruct.r1 = instruct.rd;
instruct.rd = 0;
}
return instruct;
}
