[OE-core] [PATCH 1/2] feature-arm-thumb.inc: Use thumb instruction by default if TUNE_FEATURES thumb

[Koen Kooi]

Op 11 jan. 2014, om 16:16 heeft Andrei Gherzan <andrei at gherzan.ro> het volgende geschreven:

> 
> 
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> On Sat, Jan 11, 2014 at 5:10 PM, Koen Kooi <koen at dominion.thruhere.net> wrote:
> 
> Op 11 jan. 2014, om 16:08 heeft Andrei Gherzan <andrei at gherzan.ro> het volgende geschreven:
> 
> > Avoid a confusion when including thumb in TUNE_FATURES. In the curent behavior,
> > if I include thumb in TUNE_FATURES, ARM_THUMB_M_OPT will be "-marm" which makes
> > no sense for me as a default behavior. Obviously I can change this by using
> > ARM_INSTRUCTION_SET = thumb. But this seems strange and confusing. So let's do
> > it the other way around: have thumb instructions as default when TUNE_FATURES
> > contains "thumb" and switch to "arm" instructions when ARM_INSTRUCTION_SET is
> > "arm".
> 
> Since ARM_INSTRUCTION_SET is unset for most things this will change the default, are you sure that this is what you want?
> 
> I am aware of that but still, do you find it normal to add thumb as TUNE_FEATURE and get your self with arm instructions flag?

No, but I absolutely hate the ARM tune stuff in OE-core, you pretty much need anonymous python methods to change things on a distro level, which is crazy. It took me 2 weeks and a lot of help from Khem to switch angstrom to thumb2 mode on armv7a.

> And generally people adapt if changes make sense :)

What we actually need here is a way to say "this cpu can't to full ARM mode". Which is hard, since we are treating thumb as a superset instead of a subset. 

regards,

Koen