Dot Extensions Used in the Right Hand Side of Equations

Dot  Extension	Function  Description	When Used With
		Input Only Pins	Registered Nodes	Registered Output Pins	Combinatorial Nodes	Combinatorial Output Pins
.COM	Combinatorial Feedback (from register data input)	Illegal	Emulated	Emulated	Illegal	Recommended
.D	Combinatorial Feedback from Register Data Input	Illegal	Emulated	Emulated	Illegal	Illegal
.FB*	Register Feedback	Illegal	Allowed	Recommended	Illegal	Illegal
.PIN	Pin Feedback	Allowed**	Illegal	Recommended	Illegal	Recommended
.Q*	Register Feedback	Illegal	Allowed	Allowed	Illegal	Illegal
None	Input or Node Feedback	Recommended	Recommended	Allowed***	Recommended	Allowed***

* .FB always represents the non-inverted feedback of the signal. .Q feedback is inverted if istype'invert' is also used.
** If you use .PIN on an input only signal, you must use it on all occurrances of that signal.
*** Such cases are ambiguous and typically result in pin feedback.
See Feedback Specification - .Q and .FB for details.