[U-Boot] io.h

[Scott Wood]

On Sat, Dec 19, 2009 at 11:40:40AM +0330, seyyed morteza havaedgi wrote:
> I working on mpc8272. in the file io.h there is  "twi 0,RA,0" instruction.
> what this instruction means and what it does? In accordance with powerpc programmers manual this instruction must do nothing because the TO field is zero.

It turns a data dependency on RA into a flow control dependency (even though
the decision always ends up being not to trap), which can then be ordered by
a following isync.

-Scott