Added negative offsets variables propagator.

extension.properties

@@ -1,5 +1,5 @@
 name=@extname@
 description=Loader for Sega Mega Drive / Genesis ROMs
 author=Dr. MefistO
-createdOn=07.04.2019
+createdOn=
 version=@extversion@

src/main/java/sega/NegVariableBaseReg.java

@@ -0,0 +1,7 @@
+package sega;
+
+public enum NegVariableBaseReg {
+	A4,
+	A5,
+	A6
+}

src/main/java/sega/SegaAnalyzer.java

@@ -0,0 +1,114 @@
+package sega;
+
+import java.math.BigInteger;
+import java.util.List;
+
+import ghidra.app.services.AbstractAnalyzer;
+import ghidra.app.services.AnalyzerType;
+import ghidra.app.util.importer.MessageLog;
+import ghidra.framework.options.OptionType;
+import ghidra.framework.options.Options;
+import ghidra.program.model.address.Address;
+import ghidra.program.model.address.AddressSetView;
+import ghidra.program.model.lang.Register;
+import ghidra.program.model.lang.RegisterValue;
+import ghidra.program.model.listing.ContextChangeException;
+import ghidra.program.model.listing.Function;
+import ghidra.program.model.listing.FunctionIterator;
+import ghidra.program.model.listing.FunctionManager;
+import ghidra.program.model.listing.Program;
+import ghidra.program.model.listing.ProgramContext;
+import ghidra.program.model.symbol.Symbol;
+import ghidra.program.model.symbol.SymbolTable;
+import ghidra.program.model.symbol.SymbolType;
+import ghidra.util.exception.CancelledException;
+import ghidra.util.task.TaskMonitor;
+
+public class SegaAnalyzer extends AbstractAnalyzer {
+
+	private static final long DEF_BASE_ADDR = 0xFF8000;
+	private static final String OPTION_BASE_REG = "Base Register";
+	private static final String OPTION_BASE_VAL = "Base Address";
+	private NegVariableBaseReg baseReg = NegVariableBaseReg.A6;
+	private String baseAddr = String.format("0x%06X", DEF_BASE_ADDR); 
+
+	private static boolean isSegaLoader(Program program) {
+		return program.getExecutableFormat().equalsIgnoreCase(SegaLoader.LOADER_NAME) ||
+				program.getExecutableFormat().equalsIgnoreCase("Sega Genesis/MegaDrive ROM file v.2");
+	}
+
+	public SegaAnalyzer() {
+		super("Negative Offset Variables", "Finds variables like -$XXXX(Ax) and sets specified base address", AnalyzerType.FUNCTION_ANALYZER);
+	}
+
+	@Override
+	public boolean getDefaultEnablement(Program program) {
+		return isSegaLoader(program);
+	}
+
+	@Override
+	public boolean canAnalyze(Program program) {
+		return isSegaLoader(program);
+	}
+
+	@Override
+	public void registerOptions(Options options, Program program) {
+		options.registerOption(OPTION_BASE_REG, OptionType.ENUM_TYPE, baseReg, null, "Register which is used in -$XXXX(Ax) expressions");
+
+		options.registerOption(OPTION_BASE_VAL, OptionType.STRING_TYPE, baseAddr, null, "Hexadecimal Base address for negative variables. 0xFF8000, for ex.");
+	}
+
+	@Override
+	public void optionsChanged(Options options, Program program) {
+		super.optionsChanged(options, program);
+
+		baseReg = options.getEnum(OPTION_BASE_REG, NegVariableBaseReg.A6);
+		baseAddr = options.getString(OPTION_BASE_VAL, baseAddr);
+	}
+
+	@Override
+	public boolean added(Program program, AddressSetView set, TaskMonitor monitor, MessageLog log)
+			throws CancelledException {
+
+		Address resetAddr = null;
+
+		SymbolTable symTable = program.getSymbolTable();
+		List<Symbol> resets = symTable.getLabelOrFunctionSymbols(VectorsTable.VECTOR_NAMES[1], program.getGlobalNamespace());
+		FunctionManager funcMgr = program.getFunctionManager();
+		ProgramContext ctx = program.getProgramContext();
+		Register reg = program.getRegister(baseReg.name());
+
+		for (Symbol sym: resets) {
+			if (sym.getSymbolType() == SymbolType.FUNCTION) {
+				resetAddr = sym.getAddress();
+				break;
+			}
+		}
+
+		if (resetAddr == null) {
+			return false;
+		}
+
+		FunctionIterator it = funcMgr.getFunctions(set, true);
+
+		while (it.hasNext()) {
+			Function func = it.next();
+
+			AddressSetView as = func.getBody();
+
+			if (as.getMinAddress().equals(resetAddr) || ctx.getRegisterValue(reg, as.getMinAddress()) != null) {
+				continue;
+			}
+
+			RegisterValue regVal = new RegisterValue(reg, BigInteger.valueOf(Long.decode(baseAddr)));
+			try {
+				ctx.setRegisterValue(as.getMinAddress(), as.getMaxAddress(), regVal);
+			} catch (ContextChangeException e) {
+				return false;
+			}
+		}
+
+		return true;
+	}
+
+}

src/main/java/sega/SegaLoader.java

@@ -53,12 +53,14 @@
  */
 public class SegaLoader extends AbstractLibrarySupportLoader {
 
+	public static final String LOADER_NAME = "Sega Mega Drive / Genesis Loader";
+
 	private VectorsTable vectors;
 	private GameHeader header;
 
 	@Override
 	public String getName() {
-		return "Sega Mega Drive / Genesis Loader";
+		return LOADER_NAME;
 	}
 
 	@Override

src/main/java/sega/VectorsTable.java

@@ -13,7 +13,7 @@ class VectorsTable implements StructConverter {
 	private static final int VECTORS_SIZE = 0x100;
 	private static final int VECTORS_COUNT = VECTORS_SIZE / 4;
 
-	private static final String[] VECTOR_NAMES = {
+	public static final String[] VECTOR_NAMES = {
 			"SSP", "Reset", "BusErr", "AdrErr", "InvOpCode", "DivBy0", "Check", "TrapV", "GPF", "Trace",
 			"Reserv0", "Reserv1", "Reserv2", "Reserv3", "Reserv4", "BadInt", "Reserv10", "Reserv11",
 			"Reserv12", "Reserv13", "Reserv14", "Reserv15", "Reserv16", "Reserv17", "BadIRQ", "IRQ1",