Sheesh... I missed it somehow, but it is in there. ED & EDMK did support ASCII mode, and used x'3x' zones in that case.
This old, possibly original (it has no date), Principles of Operation was a whopping 168 pages. But I haven't read the whole thing :-). ED & EDMK are listed in the "Logical Operations" section, whereas PACK & UNPK are in the "Decimal Arithmetic" section. You know which pair can cause a S0C7 though. sas On Sat, Aug 8, 2020 at 9:29 PM Charles Mills <charl...@mcn.org> wrote: > ED was not part of the original S/360 instruction set? Did you look under > Decimal Instructions? > > Charles > >