PPC WWC+lwsync+addr "WWC+lwsync+addr" { 0:r2=x; 1:r2=x; 1:r4=y; 2:r2=y; 2:r5=x; } P0 | P1 | P2 ; li r1,2 | lwz r1,0(r2) | lwz r1,0(r2) ; stw r1,0(r2) | lwsync | xor r3,r1,r1 ; | li r3,1 | li r6,1 ; | stw r3,0(r4) | stwx r6,r3,r5 ; ~exists (1:r1=2 /\ 2:r1=1 /\ x=2)