echo_buf
u8 echo_buf[N_TTY_BUF_SIZE];
return ldata->echo_buf[MASK(i)];
return &ldata->echo_buf[MASK(i)];
op = echo_buf(ldata, *tail + 1);
num_chars = echo_buf(ldata, *tail + 2);
c = echo_buf(ldata, tail);
if (echo_buf(ldata, tail) == ECHO_OP_START) {
if (echo_buf(ldata, tail + 1) == ECHO_OP_ERASE_TAB)