You could use: - System call ("sc" mnemonic). Usually used for calls into OS kernels - Unconditional trap instructions. Usually used for software breakpoints - Program interrupt. i.e. an illegal opcode. Usually this is used as an alternative to unconditional trap for software breakpoints - Debug interrupt. i.e. putting a hardware breakpoint when a PC has a sertain address.
Note that with exception of the first solution, you might interfier with the debugger. i.e. debugger to think the processors stopped due to its breakpoints, and your interrupt handler routine will never be called when you a debugging the application.
but i don't know if this is the right for me. Could i assing several priority levels wit the "system call"?
I am programming a simple preemptive OS(3 tasks). For this i need two several priority levels for my tasks one higher then the other. The PIT should cause the change by causing one of the two interrupts.