HelenOS sources

BMCR_SPD_1000     580 uspace/drv/nic/rtl8169/driver.c 	bmcr &= ~(BMCR_DUPLEX | BMCR_SPD_100 | BMCR_SPD_1000);
BMCR_SPD_1000     592 uspace/drv/nic/rtl8169/driver.c 		bmcr |= BMCR_SPD_1000;
HelenOS homepage, sources at GitHub