Subject: help with assembly (2)
To: None <port-xen@netbsd.org>
From: Manuel Bouyer <bouyer@antioche.lip6.fr>
List: port-xen
Date: 01/20/2005 20:52:00
Hi,
Again I'm stuck with some assembly code (I don't know much about i386 assembly,
and I've never mixed assembly and C). I have this code in xen/i386/vector.S:
#define hypervisor_asm_unmask(num) \
movl irq_to_evtchn + (num) * 4,%ecx ;\
movl HYPERVISOR_shared_info,%eax ;\
lock ;\
btrl %ecx,EVENTS_MASK(%eax)
(BTW, what does the "lock" instruction ?)
I need to add a call to this C function at the end of this asm
statement:
pirq_notify(num)
num being a constant. The prototype for the function is:
void pirq_notify(int irq);
I tried
pushl $(num) ;\
call _C_LABEL(pirq_notify)
but I get a page fault trap at the first call, with something that doesn't
make much sense on the stack. So I guess I missed something, but I don't
know what ... I assume registers are callee-saved, but maybe I'm wrong
on this.
--
Manuel Bouyer <bouyer@antioche.eu.org>
NetBSD: 26 ans d'experience feront toujours la difference
--