DEVSET_NIX
#define DR_GET_BOARD_DEVUNIT(sb, ut, un) (&((sb)->b_dev[DEVSET_NIX(ut)][un]))
bp->b_dev[DEVSET_NIX(SBD_COMP_CPU)] = GETSTRUCT(dr_dev_unit_t,
bp->b_dev[DEVSET_NIX(SBD_COMP_MEM)] = GETSTRUCT(dr_dev_unit_t,
bp->b_dev[DEVSET_NIX(SBD_COMP_IO)] = GETSTRUCT(dr_dev_unit_t,
FREESTRUCT(bp->b_dev[DEVSET_NIX(SBD_COMP_MEM)],
bp->b_dev[DEVSET_NIX(SBD_COMP_MEM)] = NULL;
FREESTRUCT(bp->b_dev[DEVSET_NIX(SBD_COMP_CPU)],
bp->b_dev[DEVSET_NIX(SBD_COMP_CPU)] = NULL;
FREESTRUCT(bp->b_dev[DEVSET_NIX(SBD_COMP_IO)],
bp->b_dev[DEVSET_NIX(SBD_COMP_IO)] = NULL;