[sv-bc] RE: Query related with signedness of an expression.

There were similar discussions in threads beginning at

http://www.eda.org/sv-bc/hm/10532.html and
http://www.eda.org/sv-bc/hm/10915.html .

Shalom

From: owner-sv-bc@eda.org [mailto:owner-sv-bc@eda.org] On Behalf Of Steven Sharp
Sent: Friday, November 16, 2012 22:29
To: Dhiraj Kumar Prasad; sv-bc@eda.org
Cc: Dhiraj Kumar Prasad
Subject: [sv-bc] RE: Query related with signedness of an expression.

In this case, var1 is unsigned.  A single element of var1, such as var1[0], is of type reg2 and is signed.  But var1 was not declared as signed, so it is unsigned.  In fact, there is no way to declare it to be signed.  The declaration grammar only allows you to declare one of the array levels to be signed.  This is a deficiency in the language, but that is how it was defined.  For a discussion of this deficiency, see

http://www.eda.org/svdb/view.php?id=1291


From: owner-sv-bc@eda.org<mailto:owner-sv-bc@eda.org> [mailto:owner-sv-bc@eda.org]<mailto:[mailto:owner-sv-bc@eda.org]> On Behalf Of Dhiraj Kumar Prasad
Sent: Friday, November 16, 2012 3:27 AM
To: sv-bc@eda.org<mailto:sv-bc@eda.org>
Cc: Dhiraj Kumar Prasad
Subject: [sv-bc] Query related with signedness of an expression.

Hello,

I have an query related with signedness of the expression.

Please see the following example

module top(output reg [7:0] out1);

typedef reg signed [1:0] reg2;
typedef reg2 [1:0] reg4;

reg4 var1;

always_comb
begin
        var1 = '1;
        out1 = var1;
end
endmodule

Here the var1 should be treated as signed or unsigned. I am seeing the different result in different standard tools. Some tool's are assigning out1 with 8'b11111111 (treated as signed) while some other tools are assigning out1 with 8'b00001111.

So my query is should var1 be treated as signed or unsigned ??

Regards,
dhiRAj


--
This message has been scanned for viruses and
dangerous content by MailScanner<http://www.mailscanner.info/>, and is
believed to be clean.

--
This message has been scanned for viruses and
dangerous content by MailScanner<http://www.mailscanner.info/>, and is
believed to be clean.
---------------------------------------------------------------------
Intel Israel (74) Limited

This e-mail and any attachments may contain confidential material for
the sole use of the intended recipient(s). Any review or distribution
by others is strictly prohibited. If you are not the intended
recipient, please contact the sender and delete all copies.

-- 
This message has been scanned for viruses and
dangerous content by MailScanner, and is
believed to be clean.