[okl4-developer] example of "System call exception "

[David Given]

uf65ca wrote:
> Can someone explain a bit more about "System call exception"? what would
> cause this kind of exception? an example would be appreciated. TIA.

When a thread makes a system call, it gets halted and its pager gets
sent a message that allows it to perform some action. Once finished, the
pager can restart the thread, after possibly tinkering with its registers.

Right now, the example I'm playing with is the ARM; the SWI instruction
triggers a system call. For Intel, I think the INT instruction does it.

I'd post some code, but unfortunately it's all on my other machine. The
documentation's fairly clear, though, but not easy to find; it's in the
platform-specific appendix (search for 'syscall emulation').

-- 
David Given
dg at cowlark.com