Use of virtual Interface

[ramnarayan]

Hi,
What is the use of virtual interface in systemverilog?
Why can't we use interface instead of virtual interface?

Thanks in advance.

Regards
Ramnarayan

 

[Jonathan Bromley]

On Sat, 12 Jan 2008 00:42:00 -0800 (PST),
ramnarayan <ramlh2004@gmail.com> wrote:

What is the use of virtual interface in systemverilog?

It's a pointer or reference to an existing interface instance.
Verification code can use it to manipulate signals (and other
things) in an interface, without needing to know the exact
hierarchical name of that interface. Connection from the
verification code to the existing interface is established
at run-time, by assigning an interface's instance name to
the virtual interface variable.

Why can't we use interface instead of virtual interface?

Because an interface's instance name is not a variable and
cannot be changed at run-time.

Dave Rich and I have an upcoming paper at DVCon next month
describing an alternative way to connect your verification
code to the Verilog instance hierarchy, using object references
instead of virtual interfaces. The paper will likely be
made available on our website in March.
--
Jonathan Bromley, Consultant

DOULOS - Developing Design Know-how
VHDL * Verilog * SystemC * e * Perl * Tcl/Tk * Project Services

Doulos Ltd., 22 Market Place, Ringwood, BH24 1AW, UK
jonathan.bromley@MYCOMPANY.com
http://www.MYCOMPANY.com

The contents of this message may contain personal views which
are not the views of Doulos Ltd., unless specifically stated.