Hi Surya: I am not a parsing expert, but I think that you can treat "@" as an operator and make up a precedence for it for the purpose of reading it in. Not all choices may be equally good. :) You have to distinguish "real" parentheses that were written in the property from "fake" ones that get introduced in parsing. Then you could go back over your parsed structure and figure out, according to the clock flow rules, what the scope of each clocking event is. Best regards, John H. > Sender: spsaha@cal.interrasystems.com > Date: Wed, 08 Mar 2006 18:42:25 +0530 > From: Surya Pratik Saha <spsaha@cal.interrasystems.com> > X-Accept-Language: en > CC: sv-ac@eda.org > X-OriginalArrivalTime: 08 Mar 2006 13:11:27.0485 (UTC) FILETIME=[CEEBEAD0:01C642B1] > > <!doctype html public "-//w3c//dtd html 4.0 transitional//en"> > <html> > Hi John, > <br>Even if I dont consider @ as operator, I have to know the precedence > to implement sequence/property expression in an yacc file. And also the > LRM has the following rule: > <p>property_expr ::= > <br>sequence_expr > <br>... > <br>| clocking_event property_expr > <p>So in which context an item will be reduced with "clocking_event property_expr" > has to be well defined. > <p>LRM is not clear on that. > <p>John Havlicek wrote: > <blockquote TYPE=CITE>Surya: > <p>> Some days ago I asked the precedence of @ operator in assertion rule. > <br>> I did not get well defined answer, however by reading the clock flow > section, > <br>> it is understood that @ has the weakest precedence. > <p>Ed answered you that "@" is not an assertion expression operator, > <br>so your line of reasoning to deduce that the LRM example > <p>> @(posedge clk) a ##1 @(posedge clk1) s1 |=> @(posedge clk2) s2; > <p>is wrong is flawed. > <p>I will repeat Ed's answer: in SVA, "@" is not an expression > <br>operator. > <p>Best regards, > <p>John H. > <p>> X-Authentication-Warning: server.eda.org: majordom set sender to owner-sv-ac@eda.org > using -f > <br>> Date: Wed, 08 Mar 2006 15:22:41 +0530 > <br>> From: Surya Pratik Saha <spsaha@cal.interrasystems.com> > <br>> X-Accept-Language: en > <br>> X-Virus-Status: Clean > <br>> Sender: owner-sv-ac@eda.org > <br>> X-OriginalArrivalTime: 08 Mar 2006 09:55:09.0683 (UTC) FILETIME=[62CDF430:01C64296] > <br>> > <br>> <!doctype html public "-//w3c//dtd html 4.0 transitional//en"> > <br>> <html> > <br>> &nbsp; > <br>> <p>-------- Original Message -------- > <br>> <table BORDER=0 CELLSPACING=0 CELLPADDING=0 > > <br>> <tr> > <br>> <th ALIGN=RIGHT VALIGN=BASELINE NOWRAP>Subject:&nbsp;</th> > <br>> > <br>> <td>Clock flow in SV assertion</td> > <br>> </tr> > <br>> > <br>> <tr> > <br>> <th ALIGN=RIGHT VALIGN=BASELINE NOWRAP>Date:&nbsp;</th> > <br>> > <br>> <td>Wed, 08 Mar 2006 10:28:44 +0530</td> > <br>> </tr> > <br>> > <br>> <tr> > <br>> <th ALIGN=RIGHT VALIGN=BASELINE NOWRAP>From:&nbsp;</th> > <br>> > <br>> <td>Surya Pratik Saha &lt;spsaha@cal.interrasystems.com></td> > <br>> </tr> > <br>> > <br>> <tr> > <br>> <th ALIGN=RIGHT VALIGN=BASELINE NOWRAP>To:&nbsp;</th> > <br>> > <br>> <td>"sv-bc@eda.org" &lt;sv-bc@eda.org>, sv-ac@eda.org</td> > <br>> </tr> > <br>> </table> > <br>> > <br>> <p>Hi, > <br>> <br>Some days ago I asked the precedence of @ operator in assertion > rule. > <br>> I did not get well defined answer, however by reading the clock flow > section, > <br>> it is understood that @ has the weakest precedence. > <br>> <p>Considering the fact the given e.g. in LRM (page no. 282, e.g. > d) > <br>> <p>@(posedge clk) a ##1 @(posedge clk1) s1 |=> @(posedge clk2) > s2; > <br>> <p>will be parsed as: > <br>> <p>@(posedge clk) a ##1 (@(posedge clk1) s1 |=> @(posedge clk2) > s2); > <br>> <p>So (@(posedge clk1) s1 |=> @(posedge clk2) s2) will become > a property > <br>> expression. > <br>> <p>But as per assertion BNF, ## operator can not have property > expression > <br>> in RHS. So the e.g. given in LRM is wrong. > <br>> <p>Please confirm. > <br>> <pre>--&nbsp; > <br>> Regards > <br>> Surya.</pre> > <br>> &nbsp;</html> > <br>></blockquote> > > <pre>-- > Regards > Surya.</pre> > </html> >Received on Wed Mar 8 05:34:46 2006
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