HelenOS sources
DP_RBCR0 122 uspace/drv/nic/ne2k/dp8390.c pio_write_8(ne2k->port + DP_RBCR0, esize & 0xff);
DP_RBCR0 147 uspace/drv/nic/ne2k/dp8390.c pio_write_8(ne2k->port + DP_RBCR0, esize_ru & 0xff);
DP_RBCR0 223 uspace/drv/nic/ne2k/dp8390.c pio_write_8(ne2k->port + DP_RBCR0, ETH_ADDR << 1);
DP_RBCR0 241 uspace/drv/nic/ne2k/dp8390.c pio_write_8(ne2k->port + DP_RBCR0, ETH_ADDR << 1);
DP_RBCR0 301 uspace/drv/nic/ne2k/dp8390.c pio_write_8(ne2k->port + DP_RBCR0, 0);
DP_RBCR0 381 uspace/drv/nic/ne2k/dp8390.c pio_write_8(ne2k->port + DP_RBCR0, 0);
DP_RBCR0 511 uspace/drv/nic/ne2k/dp8390.c pio_write_8(ne2k->port + DP_RBCR0, size & 0xff);
HelenOS homepage, sources at GitHub