CodeUnit getCodeUnitAt(long addr) {
		if (addr == AddressMap.INVALID_ADDRESS_KEY) {
			return null;
		}
		lock.acquire();
		try {
			CodeUnitDB cu = cache.get(addr);
			if (cu != null) {
				return cu;
			}

			try {
				InstructionDB inst = getInstructionDB(addr);
				if (inst != null) {
					return inst;
				}

				DataDB data = getDataDB(addr);
				if (data != null) {
					return data;
				}
				return getUndefinedAt(addrMap.decodeAddress(addr), addr);
			}
			catch (IOException e) {
				program.dbError(e);
			}
			return null;

		}
		finally {
			lock.release();
		}
	}
Returns the code unit whose min address equals the specified address.

@param address the min address of the code unit to return 
@return CodeUnit the code unit at the specified address, or null if a code unit does not 
exist
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/code/CodeManager.java