[OE-core] ARM-tuning -- was qemuarm: should it really have TUNE_ARCH armv5te?

[Phil Blundell]

On Tue, 2012-09-11 at 11:40 -0700, Khem Raj wrote:
> On Tue, Sep 11, 2012 at 9:13 AM, Koen Kooi <koen at dominion.thruhere.net> wrote:
> > From a gcc point of view both are the same ISA, but using xscale will take in account the absurdly long pipeline on that SoC.
> 
> Not really, when you tune for XScale it will use ldrd/strd and pld if possible

Are you sure?  As far as I remember, the only effects of -mtune=xscale
are to alter some minor pipeline-related tradeoffs in code generation.
In particular, LDM is especially slow on xscale so it is usually best
avoided unless loading very large numbers of registers.

I can't think of any reason why pld would be any more beneficial on
xscale than generic v5TE, and I don't think gcc does anything special
with it in that regard.

p.