Subject: cpu functions
To: None <firstname.lastname@example.org>
From: Matt Thomas <email@example.com>
Date: 08/26/2001 17:01:48
I'm writing the stuff in cpufunc_asm.S for xscale right now and
I have a few questions:
What is the difference between clean, flush, and purge
for the cache ops? As far as I can tell, clean forces
the data in the cache to memory. (if so, what the hell
goes cleaning the I cache do). flush does a cache
invalidation. purge seems to be a clean followed by a
On the SA110, purge is identical to clean for purgeD.
Why doesn't purgeD do a Dcache invalidation while
purge purgeID does an Icache invalidation?
Since the only difference between sa110_cache_cleanID
and sa110_cache_purgeID, why not merge the two functions
into the same code and do the Icache invalidation at
start of sa110_cache_purgeID and then fall into
sa110_cache_cleanID? Since the processor will reload
the Icache for the function, why does it matter where in
the function it happens?
Assuming I'm right in the above, I'v committed a cpufunc_asm.S
which should work on XScale processors.
Matt Thomas Internet: firstname.lastname@example.org
3am Software Foundry WWW URL: http://www.3am-software.com/bio/matt/
Cupertino, CA Disclaimer: I avow all knowledge of this message