Test k5

PPC k5 (KernelFive)
"From Linux Kernel examples, load dependency barrier not needed for PPC"
(* Use sync *)
{
  a=1; b=2; c=3; d=0 ; p=a ; q=c;
  0:r5=b ; 0:r6=p;
  1:r5=d ; 1:r6=p; 1:r7=q;
}
        P0      |       P1        ;
li r1,4         | ld  r1,0,r6 ;
stw r1,0,r5     | std r1,0,r7 ;
sync            |             ;
std r5,0,r6     |            ;
                | ld r2,0,r7 ;
                | lwz r3,0,r2 ;
                | stw r3,0,r5 ;
exists (d=2)