read_tcvr_bit
(void) read_tcvr_bit(bp, tregs);
(void) read_tcvr_bit(bp, tregs);
tmp = read_tcvr_bit(bp, tregs);
(void) read_tcvr_bit(bp, tregs);
(void) read_tcvr_bit(bp, tregs);
(void) read_tcvr_bit(bp, tregs);