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cached memory vs uncached memory
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Serge Roussel
Jan 9, 2003, 2:11:42 PM1/9/03
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Hi everyone,
in Windows CE OAL documentation, it is specified about
the StartUp function that OEMAddressTable is passed to the
kernel which will create an uncached address that points
to the same physical address. What is the difference
between the cached and the uncached address range? And why
both are needed?
Thank you
Serge Roussel
Programmer/Analyst
Dean Ramsier
Jan 9, 2003, 2:41:40 PM1/9/03
to
Accesses to cached memory hit the cache, instead of going all the way out to
the memory. At some point, the cache is flushed, and the main memory is
updated with the cache contents. Cache access is significantly faster, and
results in a performance increase. Some types of memory shouldn't be
cached, especially IO memory. Writes to this type of memory must happen in
the proper sequence because it causes something to happen, and the order of
the writes are important.
the memory. At some point, the cache is flushed, and the main memory is
updated with the cache contents. Cache access is significantly faster, and
results in a performance increase. Some types of memory shouldn't be
cached, especially IO memory. Writes to this type of memory must happen in
the proper sequence because it causes something to happen, and the order of
the writes are important.
The OEMAddressTable creates both cached and uncached versions of a physical
address so the developer can make the decision about what type of access he
wants to make.
--
Dean Ramsier - eMVP
Accelent Systems
http://www.accelent.com
"Serge Roussel" <rous...@genieo.ca> wrote in message
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