Re: Missing operand for tlbie instruction on Power7

On Fri, Oct 02, 2015 at 09:24:46PM -0500, Peter Bergner wrote:

quoted

quoted

Ok, than we can just zero out r5 for example and use it in tlbie as RS,
right?

That won't assemble _unless_ your assembler is in POWER7 mode.  It also
won't do the right thing at run time on older machines.

Correct, getting this to work on both pre-power7 and power7 and later
is tricky.  One really horrible hack would be to do:

  li r0,0
  tlbie r4,0

On pre-power7, the "0" will be taken as a zero L operand and on
power7 and later, it'll be r0, but with a zero value we loaded in
the insn before.  I know, really ugly. :-)

Hide the "li 0,0" somewhere earlier, and write it as "tlbie 4,0", and
don't write a comment -- we *like* tricky!

It should really be a separate macro define for power7 and 4xx etc.;
and the macro should not be called "tlbia", but something that makes
it obvious at the usage sites that it is in fact a macro; and why a
macro anyway, a function call might be better here?


Segher