[sv-bc] RE: Evaluating bounds in array declarations

On a related note, someone recently mentioned to me that the array query methods (20.7) all return the integer type, yet arrays bounds can be more than 32 bits. This would have been OK had we not limited integers to 32-bits.

Dave

From: owner-sv-bc@eda.org [mailto:owner-sv-bc@eda.org] On Behalf Of Brad Pierce
Sent: Monday, June 27, 2011 1:18 PM
To: sv-bc
Subject: [sv-bc] RE: Evaluating bounds in array declarations

http://www.eda.org/svdb/view.php?id=1302 was similar

From: Bresticker, Shalom [mailto:shalom.bresticker@intel.com]
Sent: Monday, June 27, 2011 1:14 PM
To: Brad Pierce; sv-bc
Subject: RE: Evaluating bounds in array declarations

Isn't there a Mantis on this?

From: owner-sv-bc@eda.org [mailto:owner-sv-bc@eda.org] On Behalf Of Brad Pierce
Sent: Monday, June 27, 2011 10:42 PM
To: sv-bc
Subject: [sv-bc] Evaluating bounds in array declarations

In an array declaration, such as

         wire [constant_expression : 0] w;

is the constant_expression

     1) statically cast to 'integer' in the SV style (that is, evaluated in the context of an assignment to the signed type 'integer'), or
     2) evaluated in a self-determined context and used as is (possibly unsigned), or
     3) evaluated in a self-determined context, but then cast to an integer?

I'm guessing 3, but don't find an answer in the LRM. Why 3? Because the issue far predates SV and its static cast, and the result of self-determined context used as-is leads to strange results.

For example, does the following have 2 bits, or a huge number of bits?

       wire [ 32'b0 - 1 : 0] w1; // type(32'b0 - 1) is unsigned

For example, does the following have 7 bits or 1 bit?

       wire [ 1'b1 + 1'b1 + 1'b1 << 1 : 0] w2; // 6 == (1'b1 + 1'b1 + 1'b1 << 1)

-- Brad

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