At 15:31 -0700 on 04/15/2013, John Ehrman wrote about TRTE and new instructions:
We may have lost the original thread on this topic? Writing a macro to simulate the actions of a new (but not universally available) instruction has several merits: (1) The macro can directly emulate the new instruction, or call an internal or external subroutine; the macro-generated code can be debugged and tested on its own without requiring testing the entire application that uses it. (2) Knowing the properties of the end-user's system means you can ship a version of the application with a simple reassembly that accounts for the presence or not of the new instruction. (3) Fortunately, useful new instructions appear in groups, so a simple SYSPARM or global variable symbol value can determine which of possibly many such macros should expand to use emulation or the new instruction. John Ehrman
If the package is distributed as OCO there is also the situation where there is a CVT flag that indicates if the feature where the instruction was added is on the machine (or the current OS level requires the group containing the instruction be on the machine) so the macro can test for the flag or OS Level and then branch to either the path with the instruction or the simulation.
