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

[Aurelien Jarno]

On Tue, Aug 27, 2013 at 12:26:00AM +0100, Peter Maydell wrote:
> On 26 August 2013 22:00, Richard Henderson <address@hidden> wrote:
> > Allow the code that tcg generates to be less obtuse, passing in
> > the return address directly instead of computing it in the helper.
> 
> > +uint8_t helper_ret_ldb_mmu(CPUArchState *env, target_ulong addr,
> > +                           int mmu_idx, uintptr_t retaddr);
> 
> >  uint8_t helper_ldb_mmu(CPUArchState *env, target_ulong addr, int mmu_idx);
> 
> I thought the reason we did it this way round was to avoid having
> so many arguments to helpers that we overflowed registers and
> into the stack on some calling conventions? Or does this not make
> much difference in practice?
> 

That was indeed the idea, but I think it's a good idea to provide this
alternative for architectures supporting enough arguments in registers.

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