AArch64 CAS+data1 { 0:X1=x; 0:X3=y; 1:X1=x; 1:X3=y; } P0 | P1 ; NOP | LDR W0, [X1]; NOP | MOV W5, W0; NOP | MOV W6, #1; MOV W0, #1 | CAS W0, W6, [X1] ; STR W0, [X3] | STR W4, [X3]; STLR W0, [X1] | NOP; Observed y=1; 1:X5=1;