Re: Analog procedural assignments

Hi, Paul -
Thanks for your detailed comments on the various items recently.

Indeed, there are potentially 3 analog_expressions in the
analog_procedural_assignment, and I think the main point of
the restriction against concatenations may have been for
the rvalue, that is, for the analog_expression explicitly
in analog_variable_assignment.

analog_procedural_assignment ::= analog_variable_assignment ; // from A.6.2
analog_variable_assignment ::= analog_variable_lvalue = analog_expression
analog_variable_lvalue ::= // from A.8.5
   variable_identifier
   | variable_identifier [ analog_expression ] { [ analog_expression ] }

I can't seem to find any restrictions on the analog_expression used
to index an array.

module test;

   reg [1:0] A;
   reg [1:0] B;
   integer Y[15:0];

   analog begin
     Y[{A, B}] = 5.0; // legal?
   end
endmodule

I think the RHS of this:
> array = '{x, y, z};
is an "array literal" because of the tick ('); it's not a
concatenation.

On the other hand, in 3.3, there's an example
        a = {"Hi",b}; // OK
which I think is a concatenation. I guess this assignment can't be
inside an analog block, because of the restriction in 5.7.

-Geoffrey

Paul Floyd wrote:
> Hi
>
> In 5.7, there is this sentence:
>
> "An analog_procedural_assignment is defined is a variable assignment
> whose ..."
>
> I think that ought to be "is defined as".
>
> I'm not sure that I understand the first point following that paragraph,
> namely
>
> "— Concatenation expressions cannot be used as part of the
> analog_expression (assigning to list of values
> in the analog context is not allowed)."
>
> Firsly, analog_expression occurs 3 times in the BNF syntax: rvalue,
> array index and optional array index. I presume only the rvalue is
> intended.
>
> Is this supposed to mean that a construction like this ought to be illegal:
>
> module test;
>
> reg [8:0] A;
> reg [8:0] B;
> integer Y;
>
> analog begin
> Y = {A, B};
> end
> endmodule
>
> or should that be "array initializer", in which case a construction like
> this would be illegal:
>
> module test
> real array [2:0];
> real x, y, z;
>
> analog begin
> array = '{x, y, z};
> end
> endmodule
>
>
> Regards
> Paul Floyd

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