public boolean isRegisterStorage() {
		return varnodes != null && varnodes.length == 1 && registers != null;
	}
@return true if this is a simple variable consisting of a single register varnode
which will be returned by either the {@link Variable#getFirstStorageVarnode()} or 
{@link Variable#getLastStorageVarnode()} methods.  The register can be obtained using the 
{@link #getRegister()} method.  Keep in mind that registers
may exist in a memory space or the register space.
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/listing/VariableStorage.java