Yes, I believe this is the same issue.
Both of Anand's example cases conform to BNFs that already exist in
Annes A and elsewhere.
Either will work. Furthermore, per section 25.5,
If a port connection specifies a modport list
name in both the module instance and module header declara-
tion, then the two modport list names shall be identical. [emphasis
added]
... so the two can be combined. [One defect I notice in this
section's prose is the unwarranted bias that
the "down design" to which the interface's modport connects is a
"module", when it might also be another
interface.]
In 9058 and in the present case, some doubt exists because the prose
never refers to the unpacked
dimension syntax; nor does it explain how the dimensions of an
interface instance interact with
the modport access restrictions. We've never formally introduced the
concept of an "array of interface
modports", though the BNF suggests these exist.
The existing prose in section 25.5 was written in the spirit of
examples being more definitive than the text,
but for the text to be entirely accurate in everything, it would become
even more unreadable than it is already.
I'd recommend leaving it in its current "gentle tutorial" form and
adding the array of modport concept in a
new subsection devoted to resolving the question that wasn't asked in
either 9058 or this thread.
Add:
25.5.n Modport and interface array expressions for use in
port connections
The ports in a list_of_interface_identifiers have (possibly empty) sets
of unpacked_dimensions; the corresponding actual port expressions must
have a matching set of unpacked_dimensions (or a matching lack
thereof). Both the modport specification and the unpacked dimensions
are additional matching criteria to the interface named type used on
this port connection. The three properties (named type, modport, and
dimensions) are completely orthogonal. In an interface port actual
expression, the optional .modport_identifier clause may
appear as a subfield selection anywhere in the static prefix of the
actual interface (see section 11.5.3). It is an error for a modport
selection to be applied to an interface type which does not declare
that modport identifier, or to an interface type which already has a different
modport identifier specified; redundantly specifying the same modport
is not prohibited.
Also add to
Section 23.3.3.4 the following paragraphs:
If a port declaration with either a generic or a named
interface type has a modport specification, it serves to either select
or confirm the modports being connected. If the actual port expression
delivers an interface type without a particular modport specification,
the formal modport identifier must exist within the actual interface
type being connected, and only the connections it specifies shall be
made between corresponding elements of the actual and formal ports.
If the actual port expression adds a modport specification, or refers
to an interface type for which a modport has already been specified, it
must match the declaration's modport, and again only the modport
connections are made.
A modport specification may be given as a subfield selection anywhere
within the static prefix of an interface port expression.
Greg Jaxon
Bresticker, Shalom wrote:
Shalom
Hi there,
Here we are trying to use
array of interfaces and specify modport.
In case-1, we instantiate
array of interfaces in the submodule and specify the modport list name
in the top level module
And in case-2, we
instantiate the array of interface along with modport specified.
So, could you please
clarify which one would be the correct way?
Thanks and Regards,
-Anand
***********************************************
* CASE 1:
***********************************************
interface inf ();
logic din;
logic dout;
modport
x(output dout, input din);
modport y(inout
dout, inout din);
endinterface: inf
module sub(in, U1, out);
input [1:0] in;
output [1:0] out;
inf U1 [2];
endmodule
module top(in, out);
input [1:0] in;
output [1:0] out;
inf U1 [2] ();
sub inst_sub
(.U1(U1.x),.in(in), out(out));
endmodule
***********************************************
* CASE 2:
***********************************************
interface inf ();
logic din;
logic dout;
modport
x(output dout, input din);
modport y(inout
dout, inout din);
endinterface: inf
module sub(in, U1, out);
input [1:0] in;
output [1:0] out;
inf.x U1[2];
endmodule
module top(in, out);
input [1:0] in;
output [1:0] out;
inf U1 [2] ();
sub inst_sub (.U1(U1),
.in(in), out(out));
endmodule
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Received on Tue May 26 10:49:41 2009