[OE-core] [PATCH 1/3] Add ARM tune file overhaul based largely on work from Mark Hatle

[Phil Blundell]

On Thu, 2011-07-28 at 23:38 -0700, Khem Raj wrote:
> On 07/27/2011 08:25 AM, Phil Blundell wrote:
> > On Wed, 2011-07-27 at 09:58 -0500, Mark Hatle wrote:
> >> For the tune names..  armv5 means I want classic ARM instructions, while armv5t
> >> means I was thumb instructions.
> >>
> >> So armv5 and armv5t are distinct in the contents of the tunings.
> >
> > Ah, I see.  Does that go for v4t too?  I can imagine cases where you
> > would want to say "select the v4T ISA but generate ARM code not Thumb".
> >
> >> Yes, the mention of DSP should be using the 'e'.  What I'm not sure of is does
> >> the "dsp" capabilities actually change any of the code or support generated.  If
> >> not then we can ignore it.
> >
> > Yes.  PLD, for example, is only available in ARMv5E (not ARMv5) and this
> > will affect any code which uses __builtin_prefetch().  I don't think GCC
> > will ever open-code the saturating arithmetic instructions, but it does
> > expose the v5/v5e distinction through preprocessor macros and source
> > code might use that to select asm() statements which use those opcodes.
> 
> LDRD/STRD which are armv5e only are used by gcc IIRC

Ah yes, you're right.  Those too.

p.