Interrupt acknowledge Query

[Saravanan A <saran@cmoschips.com>]

Dear PCI Experts

I have few questions ??

1.When interrupt Acknowledge command is issued by pci master?? and what
is significance of the vector 
returned by  the interrupt controller.

2.Can INT pins  be bi-directional?? If so , when it can be
bi-directional pins??

3.What are minimum functions that should be supported for a multi
-function device  or 
when we say it is a multi-function device ??

Your suggestions/guidance is always appreciated

Thanks and rgds

Saran