@Override
	public Register getOldRegisterContaining(Address oldAddr) {
		int value = oldRegisterRangeMap.getValue(oldAddr.getOffset());
		Register oldReg = oldLanguage.getRegister(oldAddr.getNewAddress(value), 0);
		if (value == 0 && oldReg != null) {
			// NOTE: range map will return 0 if range not found - additional checking will be 
			// required to eliminate potential match
			long oldOffset = oldAddr.getOffset();
			if (oldOffset < 0 || oldOffset >= (oldReg.getOffset() + oldReg.getMinimumByteSize())) {
				return null;
			}
		}
		return oldReg;
	}
Build and validate the default address space map.  This method must be invoked following instantiation
if the default address space mapping will be used.
@throws IncompatibleLanguageException if a default mapping of the address spaces could not be identified.
@see #getNewAddressSpace(String)
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/util/LanguageTranslatorAdapter.java