PTD_ACTIVE_MSK
ptd->count = PTD_CC_MSK | PTD_ACTIVE_MSK | PTD_TOGGLE(toggle);
#define PTD_GET_ACTIVE(p) (((p)->count & PTD_ACTIVE_MSK) >> 11)
#define PTD_ACTIVE(v) (((v) << 11) & PTD_ACTIVE_MSK)