RXBUFSIZE
scc = cc = RXBUFSIZE - sc->sc_rbavail;
if (cc == RXBUFSIZE) {
#define RXBUFMASK (RXBUFSIZE-1) /* Only iff previous is a power of 2 */
#define RXHIWAT (RXBUFSIZE >> 2)
uint8_t sc_rbuf[RXBUFSIZE];
uint8_t sc_lbuf[RXBUFSIZE];
sc->sc_rbavail = RXBUFSIZE;