db_agstart
ti = bmp->db_agstart + bmp->db_agwidth * (agno & (agperlev - 1));
bmp->db_agstart = le32_to_cpu(dbmp_le->dn_agstart);
(bmp->db_agstart < 0) ||
(bmp->db_agstart > (CTLTREESIZE - 1 - bmp->db_agwidth * (MAXAG - 1))) ||
dbmp_le->dn_agstart = cpu_to_le32(bmp->db_agstart);
for (i = 5 - bmp->db_agheight, bmp->db_agstart = 0, n = 1; i > 0;
bmp->db_agstart += n;