Size = 64)
    THEN
         TEMP128 ← DEST
         IF (RDX:RAX = TEMP128)
              THEN
                    ZF ← 1;
                    DEST ← RCX:RBX;
              ELSE
                    ZF ← 0;
                    RDX:RAX ← TEMP128;
                    DEST ← TEMP128;
                    FI;
         FI
    ELSE
         TEMP64 ← DEST;
         IF (EDX:EAX = TEMP64)
              THEN
                    ZF ← 1;
                    DEST ← ECX:EBX;
              ELSE
           