HelenOS sources

Y_SIGN            308 uspace/drv/hid/ps2mouse/ps2mouse.c 		    (((packet[0] & Y_SIGN) ? 0xff00 : 0) | packet[2]);
Y_SIGN            376 uspace/drv/hid/ps2mouse/ps2mouse.c 		    (((packet[0] & Y_SIGN) ? 0xff00 : 0) | packet[2]);