HDR_START_IDX_SHIFT
#define HDR_START_IDX_MASK (0x3f << HDR_START_IDX_SHIFT)
init_sh_desc(desc, (((pdb_len + 1) << HDR_START_IDX_SHIFT) + pdb_len) |
init_job_desc(desc, (((pdb_len + 1) << HDR_START_IDX_SHIFT)) | options);
(len << HDR_START_IDX_SHIFT));