Subject: RE: sv-bc19-40
From: Jacobi, Dan (dan.jacobi@intel.com)
Date: Mon Jan 06 2003 - 01:59:27 PST
There are two other small problems related with this problem
1. The word "edge" does not appear in the keyword list under Annex B - I
recommend we add this issue to our issue list.
2. I highly recommend that we do not use the same name "edge" for a keyword
(used under A.7.5.3 in the rule that parses the syntactic category
"edge_control_specifier") and as a syntactic category name (used under A.6.5
in the rule edge ::= posedge | negedge | changed)
I suggest we change the following under A.6.5
from :
event_expression ::=
expression [ iff expression ]
| hierarchical_identifier [ iff expression ]
| [ edge ] expression [ iff expression ]
| event_expression or event_expression
| event_expression , event_expression
edge ::= posedge | negedge | changed
to:
event_expression ::=
expression [ iff expression ] -
("iff" in bold)
| hierarchical_identifier [ iff expression ]
- ("iff" in bold)
| [ event_edge_identifier ] expression [ iff expression ]
- ("iff" in bold)
| event_expression or event_expression -
("or" in bold)
| event_expression , event_expression -
(comma "," in bold)
event_edge_identifier ::= posedge | negedge | changed -
("posedge", "negedge" and "changed" in bold)
Dan Jacobi
-----Original Message-----
From: Shalom Bresticker [mailto:Shalom.Bresticker@motorola.com]
Sent: Monday, January 06, 2003 11:33 AM
To: Jacobi, Dan
Cc: sv-bc@eda.org
Subject: Re: sv-bc19-40
That was a mistake.
See http://www.boyd.com/1364_btf/report/full_pr/30.html .
Shalom
"Jacobi, Dan" wrote:
> Sorry for the late response, haven't been in for the last two weeks.
>
> This looks like my mistake the posedge and negedge can not be parsed via
the
> edge_control_specifier token.
> I suggest we drop this issue (labeled SV-BC-19-40)
>
> P.S.
> does any body know why no more than TWO edge descriptors can be used to
> describe the value transitions meaning that the following example is
> considered legal
> edge[01, 0x] clr
> and the following example is not considered legal
> edge[01, 0x, x1] clr
>
> Dan Jacobi
>
> -----Original Message-----
> From: Shalom Bresticker [mailto:Shalom.Bresticker@motorola.com]
> Sent: Sunday, December 29, 2002 10:09 AM
> To: sv-bc@eda.org
> Subject: sv-bc19-40
>
> sv-bc19-40 says,
>
> timing_check_event_control ::=
> posedge
> | negedge
> | edge_control_specifier
>
> edge_control_specifier ::= edge [ edge_descriptor [ , edge_descriptor ]
> ]
>
> The ?posedge? and ?negedge? keywords are redundant due to the fact that
> they can be parsed when parsing the
> ?edge_control_specifier? token.
>
> This issue is labeled as SV-BC-19-40.
>
> ***
>
> I don't understand this comment.
>
> This is specifically discussed in 15.4 of 1364-2001.
> It says there,
>
> "The posedge and negedge keywords can be used as a shorthand for certain
> edge-control specifiers. For example, the construct:
>
> posedge clr
>
> is equivalent to the following:
>
> edge[01, 0x, x1] clr
>
> Similarly, the construct
>
> negedge clr
>
> is the same as the following:
>
> edge[10, x0, 1x] clr
>
> However, edge-control specifiers offer the flexibility to declare edge
> transitions other than posedge and negedge. "
>
> That is, posedge and negedge could be written with edge only,
> but they deliberately exist for the sake of convenience.
>
> --
> Shalom Bresticker Shalom.Bresticker@motorola.com
> Design & Reuse Methodology Tel: +972 9 9522268
> Motorola Semiconductor Israel, Ltd. Fax: +972 9 9522890
> POB 2208, Herzlia 46120, ISRAEL Cell: +972 50 441478
>
> "The devil is in the details."
-- Shalom Bresticker Shalom.Bresticker@motorola.com Design & Reuse Methodology Tel: +972 9 9522268 Motorola Semiconductor Israel, Ltd. Fax: +972 9 9522890 POB 2208, Herzlia 46120, ISRAEL Cell: +972 50 441478"The devil is in the details."
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