Test R+isyncs

Run R+isyncs in model, using ppcmem

PPC R+isyncs
"ISyncdWW Wse ISyncdWR Fre"
Cycle=Fre ISyncdWW Wse ISyncdWR
{
0:r2=x; 0:r4=y;
1:r2=y; 1:r4=x;
}
 P0           | P1           ;
 li r1,1      | li r1,2      ;
 stw r1,0(r2) | stw r1,0(r2) ;
 isync        | isync        ;
 li r3,1      | lwz r3,0(r4) ;
 stw r3,0(r4) |              ;
exists
(y=2 /\ 1:r3=0)