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