PPC S+sync+lwsync "SyncdWW Rfe LwSyncdRW Wse" Cycle=Rfe LwSyncdRW Wse SyncdWW { 0:r2=x; 0:r4=y; 1:r2=y; 1:r4=x; } P0 | P1 ; li r1,2 | lwz r1,0(r2) ; stw r1,0(r2) | lwsync ; sync | li r3,1 ; li r3,1 | stw r3,0(r4) ; stw r3,0(r4) | ; exists (x=2 /\ 1:r1=1)