In fortran I can use Class (*) in a subroutine and use
Select Type (ir)
Type Is (Integer (Int8))
Type Is (Integer (Int16))
End Select
Does there exist any way to pass a numeric value rather than using Class (*), by using Class (Integer) for example or something similar.
Intrinsic types are not extended types, they have no common ancestor, nothing like that exist. You can use the unlimited polymorphism (class(*)) or you must indicate exact type and kind (real(dp)). You can also write type(real) in Fortran 2008, but that does not change anything, it is just a different syntax for the same.
Have a look at some common techniques for generic programming with different kinds like, for example, How to make some generic programming in fortran 90/95 working with intrinsic types , STL analogue in Fortran and others. You normally make a separate procedure for each kind and paste the code body from an include file.
