Subject: Re: [sv-ac] statement_or_null production question for pass action block
From: Arturo Salz (Arturo.Salz@synopsys.com)
Date: Sun Mar 30 2003 - 16:25:51 PST
That may well be true. However, all it takes is a simple syntax
change to modify the BNF so that the ';' before the 'else' is no
longer needed. Currently, the assert has the same form as an 'if'
and the same syntactical ambiguities as an if, which are resolved
in the same way.
Arturo
----- Original Message -----
From: "Harry Foster" <harry@verplex.com>
To: "Arturo Salz" <Arturo.Salz@synopsys.COM>; <sv-ac@eda.org>
Sent: Saturday, March 29, 2003 12:10 PM
Subject: RE: [sv-ac] statement_or_null production question for pass action block
Interesting, this opens up a boat load of potential coding problems:
always @ (push or pop or cnt or reset_n)
if (reset_n)
if ({push, pop}==2'b01)
underflow_check: assert (cnt!=0) ;
else if ({push, pop}==2'b10)
write_en = 1'b1;
The else is not associated with the 'if' statement, it is
associated with the 'assert' statement, which will turn
into a classic error.
All if will now require the extra coding of a begin end
to be safe.....
Best regards,
-Harry
---------------------------------------------------------
Harry Foster Tel 972-423-3186
Chief Architect Cell 408-234-7637
Verplex Systems, Inc. mailto:harry@verplex.com
840 Shenandoah Dr. www.verplex.com
Plano, TX 75023 www.verifiableRTL.com
-----Original Message-----
From: owner-sv-ac@server.eda.org [mailto:owner-sv-ac@server.eda.org]On
Behalf Of Arturo Salz
Sent: Saturday, March 29, 2003 1:56 PM
To: harry@verplex.com; sv-ac@server.eda.org
Subject: Re: [sv-ac] statement_or_null production question for pass
action block
Harry,
The proposed syntax is indeed as you wrote it in the
example, with a semicolon required before the 'else'
clause of the fail statement.
Arturo
----- Original Message -----
From: "Harry Foster" <harry@verplex.com>
To: <sv-ac@eda.org>
Sent: Saturday, March 29, 2003 11:39 AM
Subject: [sv-ac] statement_or_null production question for pass action block
The current proposed syntax for immediate assertions states:
immediate_assert_statement::=
assert ( expression ) action_block
action_block::=
statement_or_null [ else statement_or_null ]
statement_or_null::=
statement
| ' ; '
However, this seems to suggest that a semicolon would be
required for all pass statements. For example:
always @ (push or pop or cnt or reset_n)
if (reset_n)
if ({push, pop}==1'b01)
underflow_check: assert (cnt!=0) ; else
$error("underflow error at %m");
If this is not the intended syntax, then it seems to me
that a new type of 'statement_or_null' production would be
needed since the current definition is used throughout
the remainder standard Verilog BNF.
Best regards,
-Harry
---------------------------------------------------------
Harry Foster Tel 972-423-3186
Chief Architect Cell 408-234-7637
Verplex Systems, Inc. mailto:harry@verplex.com
840 Shenandoah Dr. www.verplex.com
Plano, TX 75023 www.verifiableRTL.com
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