6.1.2430
WHILE
 
CORE
Interpretation:
Interpretation semantics for this word are undefined.

Compilation:
( C: dest -- orig dest )

Put the location of a new unresolved forward reference orig onto the control flow stack, under the existing dest. Append the run-time semantics given below to the current definition. The semantics are incomplete until orig and dest are resolved (e.g., by REPEAT).

Run-time:
( x -- )

If all bits of x are zero, continue execution at the location specified by the resolution of orig.

See:
A.6.1.2430 WHILE.

Rationale:
Typical use: : X ... BEGIN ... test WHILE ... REPEAT ... ;
Testing:
T{ : GI3 BEGIN DUP 5 < WHILE DUP 1+ REPEAT ; -> }T
T{ 0 GI3 -> 0 1 2 3 4 5 }T
T{ 4 GI3 -> 4 5 }T
T{ 5 GI3 -> 5 }T
T{ 6 GI3 -> 6 }T

T{ : GI5 BEGIN DUP 2 > WHILE 
      DUP 5 < WHILE DUP 1+ REPEAT 
      123 ELSE 345 THEN ; -> }T
T{ 1 GI5 -> 1 345 }T
T{ 2 GI5 -> 2 345 }T
T{ 3 GI5 -> 3 4 5 123 }T
T{ 4 GI5 -> 4 5 123 }T
T{ 5 GI5 -> 5 123 }T