Run S+isync+po in model, using ppcmem
PPC S+isync+po "ISyncdWW Rfe PodRW Wse" Cycle=Rfe PodRW Wse ISyncdWW { 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) | li r3,1 ; isync | stw r3,0(r4) ; li r3,1 | ; stw r3,0(r4) | ; exists (x=2 /\ 1:r1=1)