MEM_CTBUF
seg = MEM_CTBUF;
case MEM_CTBUF:
seg->fc_memtag = MEM_CTBUF;
MEM_CTBUF, (void *)mp);
buf_type = MEM_CTBUF;
seg = MEM_CTBUF;
seg = MEM_CTBUF;
buf_type = MEM_CTBUF;