On Mon, 13 Jun 2016 11:19:06 -0700, Charles Mills wrote:
>
>Does that mean that for standard "old-fashioned" AMODE 31 72-byte savearea
>linkage I am obligated to save the high word of R1 before issuing LINK in a
>called program? If so, this would seem to be a compatibility issue for older
>code that uses LINK. Or is R1 fair game as a work register in a called
>program?
> 
I asked a similar question a while back, concerning STORAGE.  An IBM
expert explained that certain registers (0, 1, 14, 15?) are fair game for
system services.  So, if your code, even in AMODE<=31 with a 72-byte
save area guarantees to callers to preserve R1 and uses STORAGE, you
must do something more to preserve the high word.

-- gil

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