msblkencode
rp = msblkencode(rp, tb, 4, &crc);
rp = msblkencode(rp, tb, 3, 0);
rp = msblkencode(rp, cp, sc->bytespersec, &crc);
rp = msblkencode(rp, tb, 3, 0);
u_short *msblkencode(u_short *, u_char *, int, u_short *);