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EE memory access

 
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loser



Joined: 07 Feb 2005
Posts: 25

PostPosted: Thu Oct 13, 2005 7:28 pm    Post subject: EE memory access Reply with quote

hi all

something that i have always been uncertain about was memory access to different areas on the EE. ive read the section on memory access in the EE docs, and in summary they seem to be basically as follows.

0x0xxxxxxx = user memory access
0x2xxxxxxx = uncached user memory access
0x8xxxxxxx = kernel memory access
0xAxxxxxxx = uncached kernel memory access

as well as this there is the 'kernel memory range' (0x00000 - 0x80000 ?) which can only be accessed when in kernel mode. accessing the 'kernel memory range' in user mode gives an exception (TLB i think). but what about accessing user memory when in kernel mode?
if i change to kernel mode can i access memory above the 'kernel memory range' without the 0x80000000 prefix?
if there anything bad about doing so?
am i supposed to access ALL memory with the 0x80000000 prefix when in kernel mode?

is there anything wrong with accessing memory as uncached? (besides making memory access slower due to not using caches)

any other bits of information around these points would be appreciated. :)

thx
loser
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