RE: Errors in wreal BNF

Hi Cary,

I think your assessment of the items below being errors is a bit premature: wreal simply follows the interface descriptions that are also used in electrical and logic. This is a necessary requirement for Verilog-AMS. Do remember that we have not yet merged with SV - any incompatibility needs to be resolved correctly in order to maintain the underlying modeling capabilities. The modeling capabilities that are necessary for real-valued models based on wreal is a consistency between the following declarations:

  inout [3:0] cont_value_net;

  electrical [3:0] cont_value_net;

and

  inout [3:0] cont_value_net;

  wreal [3:0] cont_value_net;

As there are already a lot of models using wreal interfaces out there, we cannot simply declare the above constructs as illegal.

Also, your statement below under item 1 about arrays of wreal is not correct: wreal is a net specification, not a type specification. It is not automatically connected to a (packed) array of reals - that would require a separate declaration and continuous assignment.

I do agree that wreal is always signed so the "signed" qualifier would be superfluous. I'm not sure that this syntactic sugar does any harm. It might be a gentle reminder to the user that the value carried on such a net is signed.

Cheers,

Marq

-----Original Message-----
From: owner-verilog-ams@eda.org [mailto:owner-verilog-ams@eda.org] On Behalf Of Cary R.
Sent: Tuesday, September 27, 2011 1:26 AM
To: Verilog-AMS LRM Committee
Subject: Errors in wreal BNF

I noticed the following errors in the wreal BNF in the

2.3.1 specification. I believe these will still apply after

the merge with 1800-2009.

1. Page 42 Syntax 3-8 and page 330 A.2.1.3

Delete [range] from both lines.

wreal should not take a [range]. Arrays of wreal are

handled in the list_of_net_... part of the syntax. In SV

this range would imply a packed array, but a packed

array of reals is not valid.

2. Page 132 Syntax 6-7 and page 329 A.2.1.2

Make new lines (three) for wreal and delete the [signed]

and [range] fields for the new wreal lines.

A wreal (real value) is always signed and as was

described in 1 above, a range is not valid for a wreal.

Regards,

Cary

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