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Re: Question on hal macro: HAL_DCACHE_INVALIDATE_ALL
- From: Gary Thomas <gary at mlbassoc dot com>
- To: John Newlin <jnewlin at rawbw dot com>
- Cc: ecos-discuss at sources dot redhat dot com
- Date: Wed, 05 May 2004 19:26:36 -0600
- Subject: Re: [ECOS] Question on hal macro: HAL_DCACHE_INVALIDATE_ALL
- Organization: MLB Associates
- References: <20040505154924.X25440@shell.rawbw.com>
On Wed, 2004-05-05 at 16:50, John Newlin wrote:
> On architectures with writeback cache, should this do:
>
> writeback + invalidate
> or simply
> invalidate
If you need the data in the cache to make it to memory, then you need
to flush (writeback).
One normally invalidates the cache when it is assumed that some other
agent has [or is about to] change memory that would make the contents
of the cache incorrect. By invalidating the cache, new [read] accesses
will cause the contents to be refreshed from memory.
--
Gary Thomas <gary@mlbassoc.com>
MLB Associates
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