Re: [Qemu-devel] [PULL 5/7] tcg: Add mmu helpers that take a return address argument

[Aurelien Jarno <aurelien@aurel32.net>]

On Tue, Aug 27, 2013 at 07:53:56AM -0700, Richard Henderson wrote:
> On 08/27/2013 03:46 AM, Aurelien Jarno wrote:
> > On the other hand calling the helper is the exception more than the
> > rule (that's why they have been moved at the end of the TB), so we 
> > should not look to much at generating fast code, but rather small code
> > in order to use the caches (both TB and CPU caches) more efficiently.
> > 
> > Therefore even on x86, if we move the -1 at the helper level, it should
> > be possible to use a tail call for the stores, something like:
> > 
> >     mov    %r14,%rdi
> >     mov    %ebx,%edx
> >     xor    %ecx,%ecx
> >     lea    -0x10f(%rip),%r8        # 0x7f2541a6f69a
> >     pushq  %r8
> >     jmpq   0x7f25526757a0
> > 
> > Instead of:
> > 
> >     mov    %r14,%rdi
> >     mov    %ebx,%edx
> >     xor    %ecx,%ecx
> >     lea    -0x10f(%rip),%r8        # 0x7f2541a6f69a
> >     callq  0x7f25526757a0
> >     jmpq   0x7f2541a6f69b
> 
> Fair enough.  I'll have a go at some follow-ups then.
> 

I think this can also be done in a second time. Do you want to create a
version 3, or should I just process the current pull request and you
will provide additional patches later?

-- 
Aurelien Jarno	                        GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net