How would I go about implementing a context switch from within the interrupt?

[wmjenkinson]

How would I go about implementing a context switch from within the interrupt? I know I need to watch the interrupt nesting and only when the interrupt nesting is 0 make the switch.

[rsta2]

You have to save all registers on entry to the IRQ handler in a structure, swap the registers of the new task with this struct's contents for the context switch and reload all registers from that struct on return from the IRQ. That's not easy to realize. Also remember that many functions in Circle are not re-entrant.