Another possibility is that it is yet another undocumented instruction. Invariably the undocumented instructions are privileged. Once someone has a z196, all they have to do is attempt to execute C8x3 to see if the result is an operation exception or a privileged operation exception.
On Mon, 9 Aug 2010 11:49:27 -0400, Abe Kornelis wrote: >Martin, > >two main possibilities exist: >1) it was never assigned. Holes have occurred many times before. >2) it is assigned to a millicode instruction - IBM internal use only. > >Other - more far-fetched - possibilities include: >3) it was assigned to an instruction that that never made it to the >outside-of-IBM world. Effectively this is the same as 'never-assigned' >4) it's been reserved for a future development that IBM foresees or is >working on, but we're not to be aware of it yet. > >Cheers, >Abe Kornelis. >=============
