HelenOS sources

RCR_AB            628 uspace/drv/nic/ne2k/dp8390.c 		ne2k->receive_configuration |= RCR_AB;
RCR_AB            630 uspace/drv/nic/ne2k/dp8390.c 		ne2k->receive_configuration &= ~RCR_AB;
RCR_AB            220 uspace/drv/nic/ne2k/ne2k.c 	ne2k->receive_configuration = RCR_AB | RCR_AM;
RCR_AB            274 uspace/drv/nic/ne2k/ne2k.c 	ne2k->receive_configuration = RCR_AB | RCR_AM;
HelenOS homepage, sources at GitHub