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

[Phil Blundell]

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.

> For armv5 this gives us:
> 
> armv5, armv5t, armv5e, armv5te... add in their VFP variants and the hard float
> EABI...

Does anybody really want the hardfloat abi on armv5?  I guess it doesn't
hurt all that much to offer it, but anything that makes that monstrous
set of .inc files bigger seems like a bad thing.

p.