GRP_UK
#define GRP_BASE(memdec) (GRP_UM(memdec) & ~(GRP_UK(memdec)))
#define GRP_UK2SPAN(memdec) ((GRP_UK(memdec) + 1) << 26)
#define GRP_SIZE_IS_SET(memdec) ((GRP_UK(memdec) & (GRP_UK(memdec) + 1)) == 0)