ST_GENERIC
#define stba(va, asi, val) ST_GENERIC(va, asi, val, stb, u_int8_t)
#define stha(va, asi, val) ST_GENERIC(va, asi, val, sth, u_int16_t)
#define stwa(va, asi, val) ST_GENERIC(va, asi, val, stw, u_int32_t)
#define stxa(va, asi, val) ST_GENERIC(va, asi, val, stx, u_int64_t)