Interpretation semantics for this word are undefined.
( C: -- orig )
Put the location of a new unresolved forward reference
orig onto the control flow stack. Append the run-time
semantics given below to the current definition. The semantics
are incomplete until orig is resolved, e.g., by
THEN or ELSE.
( x -- )
If all bits of x are zero, continue execution at the
location specified by the resolution of orig.