6.1.0580
>R
to-r
CORE
Interpretation:
Interpretation semantics for this word are undefined.

Execution:
( x -- ) ( R: -- x )

Move x to the return stack.

See:
3.2.3.3 Return stack, 6.1.2060 R>, 6.1.2070 R@, 6.2.0340 2>R, 6.2.0410 2R>, 6.2.0415 2R@.

Testing:
T{ : GR1 >R R> ; -> }T
T{ : GR2 >R R@ R> DROP ; -> }T
T{ 123 GR1 -> 123 }T
T{ 123 GR2 -> 123 }T
T{  1S GR1 ->  1S }T      ( Return stack holds cells )