Re: [Qemu-ppc] [PATCH 16/16] target-ppc: Convert to new ldst opcodes

[Richard Henderson]

On 09/05/2013 04:40 AM, Benjamin Herrenschmidt wrote:
> Only nit: I find "end_mode" a very confusing identifier :-) "end"
> usually means something else ! Why not endian_mode ?

80 column wrapping.  A poor excuse, I know...

> I haven't seen the patch itself for some reason (and I'm about to go off
> for a few days). The early day powerpc endian mode can be safely ignored
> I think, I don't even remember the details myself, I think it induced
> some changes to the byte lanes ordering on the bus and thus required the
> host bridge to be adjusted.

This sounds like the ARM BE32 mode on early arms.  Now discontinued, afaik.

> The embedded PPCs have simply a per-page E bit in the TLB controlling
> the endianness of accesses through the translation, the endianness is
> "clean" in that case, and the bus doesn't flip around so it's akin to
> what P7 does but with a finer granularity.

This would be significantly harder (and slower) to emulate.  It would
require playing games at the cputlb level, and really nothing to do with
the code generation from tcg at all.


r~