PPC WRW+WR+reader+lwsync+sync
"Rfe LwSyncdRW Wse SyncdWR Fre"
Cycle=Rfe LwSyncdRW Wse SyncdWR Fre
{
0:r2=x;
1:r2=x; 1:r4=y;
2:r2=y; 2:r4=x;
3:r2=y;
}
P0 | P1 | P2 | P3 ;
li r1,1 | lwz r1,0(r2) | li r1,2 | lwz r1,0(r2) ;
stw r1,0(r2) | lwsync | stw r1,0(r2) | ;
| li r3,1 | sync | ;
| stw r3,0(r4) | lwz r3,0(r4) | ;
exists
(y=2 /\ 1:r1=1 /\ 2:r3=0 /\ 3:r1=1)
(*
Strange, forbidden in some experiment, while
simpler, apriori equivalent WRW+WR+lwsync+sync is allowed
*)