Re: [Qemu-devel] [PATCH 5/7] tcg-i386: Implement deposit operation.

[Richard Henderson <rth@twiddle.net>]

On 01/26/2011 11:01 AM, Alexander Graf wrote:
>> As far as I know, it does not happen at random.  Which seems to be 
>> what you are suggesting.
> 
> It happens on load/store and potentially helpers. The main difference
> IIUC between globals and temps is that globals are kept in registers as
> long as possible (read: until load/store or helper or tb end gets
> emitted) while temporaries are not stored back to any memory, so they
> are lost on load/store.
> 
> So what you are suggesting is basically to use a different set of
> globals for regs32 and to keep track of their usage throughout the TB,
> so we can convert on demand. We can't use temporaries for that unless we
> manually store them off on load/store/helper/tb end which means we'd
> rewrite the globals treatment in target code :).

No, what I'm suggesting is manually storing the reg32 temporaries back
to their reg64 origins in the translator immediately before issuing the
load/store/helper/tbend, at which point the generic TCG bits write back
the reg64 globals to their env origin.

Do you have a pointer to your s390x tree?



r~