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. =============
