microoptimising atomic memory ops

[Ken Werner]

On Wednesday, November 24, 2010 8:29:35 pm Peter Maydell wrote:
> This wiki page came up during the toolchain call:
> https://wiki.linaro.org/Internal/People/KenWerner/AtomicMemoryOperations/

The page was just moved to:
https://wiki.linaro.org/WorkingGroups/ToolChain/AtomicMemoryOperations

>         strex   r0, r2, [r3] # store r2 (new) into  memory pointed to
> by r3 (mem)

Initially I thought r2 could be used for the result but strex doesn't allow 
the return register to be the same as the store register. But using r0 instead 
is a good idea. 

Thanks!
Ken