🚀 go-pugleaf

Hello to all PC experts,

I have written a packet driver for ax.25 protocol (amateur packet radio).
The driver works fine but only on ATs... I'm not really an expert
on PC interiors so I wonder what are the differences between PC AT and XT ?
One could say it is the speed but the driver _does_ work on 8MHz AT
but does not or perfomrs very poorly on an XT. So what ?

The driver uses serial port and is interrupt driven. It relies
heavily on fast interrupt response as it makes "manually" every bit
of tranmitted signal. To decode received signal data transitions
trigger an interrupt which reads the system timer.
The driver uses as well system timer interrupt to analyze data
accumulated by UART interrupts.

In the name of XT users who are bothering me frequently
- and will bother more :-) - I'm begging the net for help
or suggestions.

And here are some specific questions:
- Is the interrupt controller different in an XT than in an AT ?
- Is it possible to raise UART IRQ priority over others
  to make interrupt response faster ? How to do it ?
- The timer interrupt routine services the timer-related stuff
  and issues EOI to 8259 (by calling original timer routine),
  but afterwards it does not do "iret" but continues for some
  time with data analysis and then does "iret". Will this analysis
  be interrupted when UART requests ?
- Any recomandation on on-line literature about 8259
  interrupt controller ?

Pawel