Heikki Linnakangas <heikki.linnakangas@enterprisedb.com> writes:
> The Linux kernel does this (arch/powerpc/include/asm/ppc-opcode.h):
Yeah, I was looking at that too.
> We can't copy-paste code from Linux directly, and I'm not sure I like
> that particular phrasing of the macro, but perhaps we should steal the
> idea and only use the hint on 64-bit PowerPC processors?
The info that I've found says that the hint exists beginning in POWER6,
and there were certainly 64-bit Power machines before that. However,
it might be that the only machines that actually spit up on the hint bit
(rather than ignore it) were 32-bit, in which case this would be a
usable heuristic. Not sure how we can research that ... do we want to
just assume the kernel guys know what they're doing?
regards, tom lane
