HelenOS sources

sdctl1_srst       208 uspace/drv/audio/hdaudio/stream.c 	ctl = ctl | BIT_V(uint8_t, sdctl1_srst);
sdctl1_srst       214 uspace/drv/audio/hdaudio/stream.c 	ctl = ctl & ~BIT_V(uint8_t, sdctl1_srst);
HelenOS homepage, sources at GitHub