private byte getByte(int offset, Address addr) throws UndefinedValueException {
		AddressRangeMapDB map = getRangeMap(offset);
		if (map != null) {
			Field value = map.getValue(addr);
			if (value != null) {
				return value.getByteValue();
			}
		}
		throw UNDEFINED_VALUE_EXCEPTION;
	}
Constructs a new ProgramContextDB object
@param dbHandle the handle to the database.
@param errHandler the error handler
@param language the processor language
@param addrMap the address map.
@param lock the program synchronization lock
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/register/OldProgramContextDB.java