u3: adds comments to explain unusual u3v_arvo/u3v_home requirements
/** Data structures.
**/
/* u3v_arvo: modern arvo structure.
+ ** NB: packed to perserve word alignment given [eve_d]
*/
typedef struct __attribute__((__packed__)) _u3v_arvo {
c3_d eve_d; // event number
} u3v_arvo;
/* u3v_home: all internal (within image) state.
+ ** NB: version must be last for discriminability in north road
*/
typedef struct _u3v_home {
u3a_road rod_u; // storage state
u3v_arvo arv_u; // arvo state
- c3_w ver_w; // version number XX s/b first
+ c3_w ver_w; // version number
} u3v_home;
