True, I was thinking of being in secondary addressing mode. Peter Relson has consistently said of home space mode: "Don't even consider it!". So I didn't. It is one of those "forbidden" states unless you've got a lot of internals information.
On Wed, 2012-04-11 at 08:26 +0000, [email protected] wrote: > Edward Jaffe <[email protected]> wrote > > > On 4/10/2012 11:31 AM, McKown, John wrote: > >> But that made me wonder why the z/Architecture does not specify that the > >> contents of the AR register associated with the link register in any of > >> the "branch and link" type instructions: BALR, BASR, BRAS, BRASL, and > >> BASSM will be set to 0? > >> > >> Anybody have any idea why these type of instructions don't set the AR? > > > > Unnecessary. Instruction fetch is always from the primary address space. > > No, in Home-space mode instructions are fetched from the HASN. > > Since you can't branch out of the current address space with any of the > instructions you listed, there is no reason to test or manipulate the AR. -- John McKown Maranatha! <><
