64 bit DMA on RTEMS

Leon Pollak leonp at plris.com
Fri Jul 31 18:00:13 UTC 2009


On Friday July 31 2009, Kate Feng wrote:
> Hi,
>
>    Does RTEMS compiler truly support "64 bit DMA operation"
> if the H/W (e.g. processor & data bus)  supports 64 bit data ?
> What I meant is that the compiler will not chop down the
> 64 bit data into two of 32 bit ones.  Please confirm.
Kate,
i am not sure what you mean...
In my case, I have MPC8260 like CPU which has 64bit bus for RAM and DMA 
transfers. This is done by CPU automatically.
AFAIK, DMA is done without CPU intervention and compiler can not influence on 
that.
May be you mean 64bit machines such as AMD or INTEL Pentium Dual core etc.?
-- 
Leon




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