UKBD_IN_BUF_SIZE
#define UKBD_IN_BUF_FULL (UKBD_IN_BUF_SIZE / 2) /* bytes */
uint32_t sc_input[UKBD_IN_BUF_SIZE]; /* input buffer */
if (sc->sc_inputs < UKBD_IN_BUF_SIZE) {
if (sc->sc_inputtail >= UKBD_IN_BUF_SIZE) {
if (sc->sc_inputhead >= UKBD_IN_BUF_SIZE) {