private long getNormalizedOffset(Address addr) {
		// supports unsigned space only
		long offset = addr.getOffset() - baseImageOffset;
		long maxOffset = addr.getAddressSpace().getMaxAddress().getOffset();
		if (maxOffset > 0 && offset < 0) {
			// wrap normalized otherOffset within space
			return offset + maxOffset + 1;
		}
		return offset;
	}
Returns an address map which may be used during the upgrade of old address
encodings.  If the address map is up-to-date, then this method will return
this instance of AddressMapDB.
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/map/AddressMapDB.java