------------------------------------------------------------------------------

Kamal R. Prasad
AIX Support & Test, IBM India Software Labs
Golden Enclave, Airport Road, Bangalore-560017, India
Phone : +91-80-5094963,  Internal Ext   : 2963





> [...] logic [...] to decide if it(load/store) is meant for I/O device
> or memory and probably bypasses cache as a result for I/O operations
> without the volatile keyword being used.

>The volatile keyword has nothing to do with bypassing cache in the
>memory-subsystem sense; it exists to prevent the compiler from cacheing
>"stored" values, optimizing it away, rearranging it with respect to
>other volatile-marked stores, or suchlike.

yes -that was my messup.  the volatile keyword exists to prevent the
compiler from optimizing the generated code (under the presumption that it
is general memory and/or that the memory contents can be modified by the
cpu only).
regards
-kamal

/~\ The ASCII                                                der Mouse
\ / Ribbon Campaign
 X  Against HTML                mouse@rodents.montreal.qc.ca
/ \ Email!              7D C8 61 52 5D E7 2D 39  4E F1 31 3E E8 B3 27 4B