HelenOS sources
MAC0 234 uspace/drv/nic/rtl8139/driver.c *mac0_dest = pio_read_32(rtl8139->io_port + MAC0);
MAC0 235 uspace/drv/nic/rtl8139/driver.c *mac4_dest = pio_read_16(rtl8139->io_port + MAC0 + 4);
MAC0 252 uspace/drv/nic/rtl8139/driver.c pio_write_32(rtl8139->io_port + MAC0, *val1);
MAC0 253 uspace/drv/nic/rtl8139/driver.c pio_write_32(rtl8139->io_port + MAC0 + 4, *val2);
MAC0 1157 uspace/drv/nic/rtl8169/driver.c addr->address[i] = pio_read_8(rtl8169->regs + MAC0 + i);
MAC0 1168 uspace/drv/nic/rtl8169/driver.c pio_write_8(rtl8169->regs + MAC0 + i, addr->address[i]);
HelenOS homepage, sources at GitHub