Go to a subroutine at program line LLLL if X contains a number less than or equal to nn.
Dialect exclusions: Not available in dialects before 10.
Note: Does not pop X
See also GoSubIfXEQ, GoSubIfXGE, GoSubIfXGT, GoSubIfXLT, GoSubIfXNE
GoSubIfXEQ
GoSubIfXGE
GoSubIfXGT
GoSubIfXLT
GoSubIfXNE