HelenOS sources

ANAR_100TX_HD    1663 uspace/drv/nic/rtl8139/driver.c 		anar |= ANAR_100TX_HD;
ANAR_100TX_HD    1715 uspace/drv/nic/rtl8139/driver.c 	if (anar & ANAR_100TX_HD)
ANAR_100TX_HD     645 uspace/drv/nic/rtl8169/driver.c 		anar |= ANAR_100TX_HD;
HelenOS homepage, sources at GitHub