Append the run-time semantics below to the current definition.
Place cell pair x1 x2 on the stack.
X
x1
x2
T{ 2VARIABLE 2v4 IMMEDIATE 5 6 2v4 2! -> }T T{ : cd7 2v4 [ 2@ ] 2LITERAL ; cd7 -> 5 6 }T T{ : cd8 [ 6 7 ] 2v4 [ 2! ] ; 2v4 2@ -> 6 7 }T