Re: errata/5: Bad description of implicit nets created from continuous assignments

From: Shalom Bresticker (Shalom.Bresticker@motorola.com)
Date: Mon Aug 06 2001 - 07:20:01 PDT


The following reply was made to PR errata/5; it has been noted by GNATS.

From: Shalom Bresticker <Shalom.Bresticker@motorola.com>
To: Cc: btf-bugs@boyd.com
Subject: Re: errata/5: Bad description of implicit nets created from continuous assignments
Date: Mon, 06 Aug 2001 17:11:51 +0300

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 Here's an interesting curiosity in Verilog-XL.
 
 I just encountered such a case, and it turns out you can't reference it with a hierarchial name reference.
 
 Example:
 
 module qq ( a ) ;
 output [3:0] a ;
 assign a = 2 ;
 endmodule
 
 module pp ;
 initial force qq.a = 0 ;
 endmodule
 
 will give you a message that a is undeclared in qq.
 
 From pp, it recognizes a only as an external port of qq, not as an internal signal.
 
 Shalom
 
 
 "Clifford E. Cummings" wrote:
 
> In Verilog-1995:
> - If the LHS variable of a continuous assignment drives a port, the size
> can be inferred from the port definition and the data type is assumed to be
> wire, unless otherwise declared.
 
 --
 **************************************************************************
 Shalom Bresticker Shalom.Bresticker@motorola.com
 Motorola Semiconductor Israel, Ltd. Tel #: +972 9 9522268
 P.O.B. 2208, Herzlia 46120, ISRAEL Fax #: +972 9 9522890
 **************************************************************************
 
 
 
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 Here's an interesting curiosity in Verilog-XL.
 <p>I just encountered such a case, and it turns out you can't reference
 it with a hierarchial name reference.
 <p>Example:
 <p>module qq ( a ) ;
 <br>output [3:0] a ;
 <br>assign a = 2 ;
 <br>endmodule
 <p>module pp ;
 <br>initial force qq.a = 0 ;
 <br>endmodule
 <p>will give you a message that a is undeclared in qq.
 <p>From pp, it recognizes a only as an external port of qq, not as an internal
 signal.
 <p>Shalom
 <br>
 <p>"Clifford E. Cummings" wrote:
 <blockquote TYPE=CITE>In Verilog-1995:
 <br>- If the LHS variable of a continuous assignment drives a port, the
 size
 <br>can be inferred from the port definition and the data type is assumed
 to be
 <br>wire, unless otherwise declared.</blockquote>
 
 <pre>--
 **************************************************************************
 Shalom Bresticker Shalom.Bresticker@motorola.com
 Motorola Semiconductor Israel, Ltd. Tel #: +972 9 9522268
 P.O.B. 2208, Herzlia 46120, ISRAEL Fax #: +972 9 9522890
 **************************************************************************</pre>
  </html>
 
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