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