HelenOS sources

ANAR_PAUSE       1510 uspace/drv/nic/rtl8139/driver.c 		if (anar_lp & ANAR_PAUSE)
ANAR_PAUSE       1665 uspace/drv/nic/rtl8139/driver.c 		anar |= ANAR_PAUSE;
ANAR_PAUSE       1721 uspace/drv/nic/rtl8139/driver.c 	if (anar & ANAR_PAUSE)
ANAR_PAUSE        647 uspace/drv/nic/rtl8169/driver.c 		anar |= ANAR_PAUSE;
HelenOS homepage, sources at GitHub