I guess that would only apply to deferred assertions outside procedure. If we allow concurrent assertions to be anywhere, these deferred opnes should probably be allowed too.
ed
From: Bresticker, Shalom [mailto:shalom.bresticker@intel.com]
Sent: Monday, July 12, 2010 8:46 AM
To: Eduard Cerny; Dhiraj Kumar Prasad; Korchemny, Dmitry
Cc: Surya Pratik Saha; ben@systemverilog.us; sv-bc@eda.org; sv-ac@server.eda.org; Adhip Das
Subject: RE: [sv-bc] RE: [sv-ac] Identifier usage before declaration in assertion
What about deferred assertions?
Shalom
From: Eduard Cerny [mailto:Eduard.Cerny@synopsys.com]
Sent: Monday, July 12, 2010 3:43 PM
To: Dhiraj Kumar Prasad; Korchemny, Dmitry
Cc: Bresticker, Shalom; Surya Pratik Saha; ben@systemverilog.us; sv-bc@eda.org; sv-ac@server.eda.org; Adhip Das
Subject: RE: [sv-bc] RE: [sv-ac] Identifier usage before declaration in assertion
Hi,
The example that Ben provided is a concurrent assertion, not an immediate one. If I recall correctly, there was an unwritten assumption already in the 2005 std (which should have been written...) that concurrent assertions including sequence and property declarations can be placed anywhere and access variables in their scope w/o an xmr. I believe that was done to allow placement of assertions even at the boundaries of modules rather than follow the declare-before-use rule.
Since all simulators/tools support that, perhaps it should be stated explicitly in the LRM.
Best regards,
ed
From: owner-sv-ac@eda.org [mailto:owner-sv-ac@eda.org] On Behalf Of Dhiraj Kumar Prasad
Sent: Monday, July 12, 2010 3:18 AM
To: Korchemny, Dmitry
Cc: Bresticker, Shalom; Surya Pratik Saha; ben@systemverilog.us; sv-bc@eda.org; sv-ac@server.eda.org; Adhip Das
Subject: Re: [sv-bc] RE: [sv-ac] Identifier usage before declaration in assertion
But LRM say about immediate assertion and which is equivalent to condition in if statement. So the variable reference
in assertion should be treated in same way as other variable.
-dhiRAj
Korchemny, Dmitry wrote:
I am trying to figure out how the implementation is done. Should this be written in the LRM explicitly, is a different question.
Dmitry
From: Bresticker, Shalom
Sent: Monday, July 12, 2010 10:06 AM
To: Korchemny, Dmitry; Surya Pratik Saha
Cc: ben@systemverilog.us<mailto:ben@systemverilog.us>; sv-bc@eda.org<mailto:sv-bc@eda.org>; sv-ac@server.eda.org<mailto:sv-ac@server.eda.org>; Adhip Das
Subject: RE: [sv-ac] Identifier usage before declaration in assertion
But that does not answer the question of why an assertion is different. It does not work that way for other constructs. The exception is task and function calls, and those ARE described in the LRM.
Shalom
From: Korchemny, Dmitry
Sent: Monday, July 12, 2010 10:04 AM
To: Surya Pratik Saha
Cc: Bresticker, Shalom; ben@systemverilog.us<mailto:ben@systemverilog.us>; sv-bc@eda.org<mailto:sv-bc@eda.org>; sv-ac@server.eda.org<mailto:sv-ac@server.eda.org>; Adhip Das
Subject: RE: [sv-ac] Identifier usage before declaration in assertion
Since at the point of this assertion this signal is unknown, it is then searched as an XMR. This is my guess, I could not find any explicit explanation in the LRM.
Dmitry
From: Surya Pratik Saha [mailto:spsaha@cal.interrasystems.com]
Sent: Monday, July 12, 2010 10:01 AM
To: Korchemny, Dmitry
Cc: Bresticker, Shalom; ben@systemverilog.us<mailto:ben@systemverilog.us>; sv-bc@eda.org<mailto:sv-bc@eda.org>; sv-ac@server.eda.org<mailto:sv-ac@server.eda.org>; Adhip Das
Subject: Re: [sv-ac] Identifier usage before declaration in assertion
But why? What is special in assertion or any other scope (I am not sure for any other scope similar behaviour is followed or not) for that it will be treated as XMR?
Regards
Surya
-------- Original Message --------
Subject: Re:[sv-ac] Identifier usage before declaration in assertion
From: Korchemny, Dmitry <dmitry.korchemny@intel.com><mailto:dmitry.korchemny@intel.com>
To: Bresticker, Shalom <shalom.bresticker@intel.com><mailto:shalom.bresticker@intel.com>, ben@systemverilog.us<mailto:ben@systemverilog.us> <ben@systemverilog.us><mailto:ben@systemverilog.us>, Surya Pratik Saha <spsaha@cal.interrasystems.com><mailto:spsaha@cal.interrasystems.com>
Cc: "sv-bc@eda.org"<mailto:sv-bc@eda.org> <sv-bc@eda.org><mailto:sv-bc@eda.org>, "sv-ac@server.eda.org"<mailto:sv-ac@server.eda.org> <sv-ac@eda.org><mailto:sv-ac@eda.org>, Adhip Das <adhip@cal.interrasystems.com><mailto:adhip@cal.interrasystems.com>
Date: Monday, July 12, 2010 12:25:39 PM
I think that in this case aa is treated as XMR.
Thanks,
Dmitry
From: owner-sv-ac@eda.org<mailto:owner-sv-ac@eda.org> [mailto:owner-sv-ac@eda.org] On Behalf Of Bresticker, Shalom
Sent: Monday, July 12, 2010 9:54 AM
To: ben@systemverilog.us<mailto:ben@systemverilog.us>; Surya Pratik Saha
Cc: sv-bc@eda.org<mailto:sv-bc@eda.org>; sv-ac@server.eda.org<mailto:sv-ac@server.eda.org>; Adhip Das
Subject: RE: [sv-ac] Identifier usage before declaration in assertion
Ben,
6.21 says, "A variable declaration shall precede any simple reference (non-hierarchical) to that variable."
Shalom
From: owner-sv-ac@eda.org<mailto:owner-sv-ac@eda.org> [mailto:owner-sv-ac@eda.org] On Behalf Of ben cohen
Sent: Monday, July 12, 2010 9:31 AM
To: Surya Pratik Saha
Cc: sv-bc@eda.org<mailto:sv-bc@eda.org>; sv-ac@server.eda.org<mailto:sv-ac@server.eda.org>; Adhip Das
Subject: Re: [sv-ac] Identifier usage before declaration in assertion
LRM 3.12 Compilation and elaboration addresses the elaboration.
Elaboration takes care of the variables being declared in the design. LRM: "Not all syntax and semantics can be checked during
the compilation process."
Ben Cohen
On Sun, Jul 11, 2010 at 11:21 PM, Surya Pratik Saha <spsaha@cal.interrasystems.com<mailto:spsaha@cal.interrasystems.com>> wrote:
Hi,
For the following case:
module top(input clk, input [3:0] iT, output [3:0] oT);
assert property (@(posedge clk) (aa == 4'b0000)) ;
reg [3:0] aa;
always @(posedge clk)
aa <= iT;
assign oT = aa;
endmodule // top
All the standard simulators pass the case. Please note that 'aa' is used before it is declaration in the assertion statement. I could not find any text in the LRM regarding this. What is the reason of this?
-- Regards Surya -- This message has been scanned for viruses and dangerous content by MailScanner, 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<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. --------------------------------------------------------------------- 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<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.Received on Mon Jul 12 05:49:55 2010
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