Re: [Qemu-devel] [PATCH 01/10] target-arm: Make Neon helper routines use correct FP status

[Aurelien Jarno]

On Sun, Apr 03, 2011 at 12:21:49PM +0100, Peter Maydell wrote:
> On 3 April 2011 12:10, Blue Swirl <address@hidden> wrote:
> > On Sun, Apr 3, 2011 at 1:51 PM, Peter Maydell <address@hidden> wrote:
> >> But I can submit a patch to do that if it's the right thing.
> >
> > It's not so much about correctness, but performance. All generated
> > code already has access to global env, so passing it via helper
> > arguments requires extra instructions which can be avoided.
> 
> Yes; I meant "right thing" in the more general senses of "is best
> practice for qemu code" and "causes my patches to be accepted" :-)
> 
> Anyway, how about I do a version of this patch which moves
> the affected neon helpers to op_helper.c rather than adding
> an env parameter (which would avoid changes that a cleanup
> would just have to revert); but leave patch 10 as-is (that's
> the one which is touching vfp helpers, but it is just cleanup
> which isn't changing how they handle env) ?
> 
> Then I can do a separate patchset to move other helpers,
> rather than tangling a code-cleanup patchset with Neon
> correctness fixes.
> 
 
This solution looks fine for me. That said, I am not sure moving
everything to op_helper.c is the best solution. I would rather go for
compiling *_helper.c with HELPER_CFLAGS, which avoids having one big
file which is messy to edit, and long to compile.

I leave you choose what you prefer.

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