[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 22:59 -0700, Khem Raj wrote:
> here I guess we have to say AVAILTUNES += "arm920t arm920"
> where arm920 is arm mode and 920t is thumb mode. but anyway I would 
> prefer that thumb is optionally added provided user asked for it
> through DISTRO/MACHINE features then we should first make sure
> that selected machine has thumb feature and if yes for both then we 
> should enable -mthumb compiler option which now it enable when thumb 
> appears in TUNE_FEATURES

I don't think we want to go down the road of inventing CPU names for
ARM-state variants of Thumb-capable cores.  (In other words, we
shouldn't start putting things like "arm920" in AVAILTUNES when there
isn't actually a core named arm920.)

Fundamentally I think you're right that the choice between ARM-state and
Thumb-state (for t1 at least) ought to be under the control of the
DISTRO and not selected purely on the basis of the hardware
capabilities.  For t2 it is a bit less of a clear-cut issue but, if
there are genuinely people making ARMv7 cores with the Thumb decoder
removed, I guess we need to have that same switch there as well.

p.