I was programming in Turbo Pascal for many years, accordingly in real mode. Now I tried to change and start develop aplications in Free Pascal, protected mode. However, many things that works in RM doesn't works in PM, indeed. I downloaded a lot of examples, but they didn't help me (many of them, althrough some people say it helps, my IDE even doesn't compile it due syntax errors !!). I know about lock code and data, DS save, but I'm a beginner at this, beyond there isn't many tutorials (if any). So, if you have any experiences (a lot of ;) ), I would be very gladly.

My aspiration is there:


It has only 80 kB, but one big problem:

- every 11st tact (on 18.2 Hz counter) program report Run Time error 216 (General Protected Fault). In all likelihood it occur every Sound Blaster interrupt, because DMA mix buffer is 32 kB in size and it's divided up to four parts (in quality 11 kHz 8 bits mono takes one part 13.5 tact).
- at all times error is invoked by the last instruction in the INT handler, no mater which changes are done.
- if INT routine has no code, error occur anyway, but FPC don't show any line.
- if I run program from FPC again after it exit with RE216, it run normaly, but belike Sound card doesn't generate interrupt.

So, if you have any time, please see it and if you find any probable problem, tell me (in which line, what it's and how to solve). Thanks very much in advance.