> Does this mean that there should be variants of DIAG where some > of the parameters (&RY or &DISP) could be omitted? If so, should the > macro take care of such omissions?
Personally, I wouldn't entertain the possibility of omitting the &DISP parameter, since that's the parameter that identifies the Diag function that is to be performed and there's probably no reasonable default. It might be reasonable to allow the coder to omit the &Ry parameter and have it default to, say, 0. In that case, though, I would probably rearrange the order of the operands to make it Diag Disp,Rx,Ry. (I used the Rx,Ry,Disp order to conform to the order used by the VM version, in which case the coder could just specify a 0 when the Ry operand is unused; the macro documentation (prolog, commentary, etc.) should clearly spell this out.) - mb
