wdr_sector
wdc_c->r_sector = CHP_READ_REG(chp, wdr_sector);
CHP_WRITE_REG(chp, wdr_sector, sector);
sn = CHP_READ_REG(chp, wdr_sector);
sn = CHP_READ_REG(chp, wdr_sector);
chp->cmd_ioh, wdr_sector & _WDC_REGMASK);
sn = bus_space_read_2(chp->cmd_iot, iohs[wdr_sector], 0);
sn = CHP_READ_REG(chp, wdr_sector);
chp->cmd_ioh, wdr_sector & _WDC_REGMASK);