<snip> All 64 bits of general registers 14, 15, 0, and 1, and the corresponding ARs are volatile across any call or service. </snip>
Actually, the linkage convention is that AR14 and the high half of GR14 are not volatile. That matches what the PR instruction accomplishes (having saved all the regs via BAKR or PC). Of course the high half of GR14 might have been used in the call linkage itself if using something like "BASR" in AMODE 64 to pass control. I won't claim, by the way, that all services meet this "high standard" with respect ot AR14/GR14, so it would be best not to rely much on such behavior, so in general assume that AR14 and all of GR14 are clobbered. Services such as GETMAIN (STORAGE OBTAIN) and FREEMAIN (STORAGE RELEASE) do meet the standard. Peter Relson z/OS Core Technology Design
