#define RCSR (*((volatile uint16_t *)0177560))
#define RBUF (*((volatile uint16_t *)0177562))
#define XCSR (*((volatile uint16_t *)0177564))
#define XBUF (*((volatile uint16_t *)0177566))
while((XCSR
&& 0200) == 0) continue;
while((RCSR
&& 0200) == 0) continue;
while (count
--) continue;