Re: [sv-ac] 928 Proposal Updated

Hi Ed:

Here are some examples.

   sequence s1(logic [1:0] v);
      v[0] ##1 v[1];
   endsequence

Suppse that a is of type logic [4:0].
I expect the following instances to be legal:

   s1(a[4:3])  // a[4] goes to v[1], a[3] goes to v[0]
   s1(a[3])    // 1'b0 goes to v[1], a[3] goes to v[0]
   s1(a[2:0])  // a[2] is truncated, a[1] goes to v[1], a[0] goes to v[0]

I expect

   sequence s2(logic [1:0] v);
      v[3] ##1 v[4];
   endsequence

to yield a compilation error at the sequence declaration, 
even though a passing by substitution might make sense for
the instance

   s2(a[4:3])

What do you think?

J.H.

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> Date: Thu, 29 Jun 2006 06:02:40 -0700
> Thread-Topic: [sv-ac] 928 Proposal Updated
> Thread-Index: Acabb6tsSsyoq+H2SSSQnbQz0tXtQwADFlGQ
> From: "Eduard Cerny" <Eduard.Cerny@synopsys.com>
> Cc: <piper@cadence.com>, <Bassam.Tabbara@synopsys.com>,
>         <dmitry.korchemny@intel.com>, <Brad.Pierce@synopsys.com>,
>         <sv-ac@eda-stds.org>
> X-OriginalArrivalTime: 29 Jun 2006 13:02:42.0070 (UTC) FILETIME=[4E6DB360:01C69B7C]
> 
> Hi John,
> 
> no, I was thinking that if we leave the pass-by-value args out, then all
> is treated as substitution, because even if it is an int or logic, by
> substituting the epxression in the property you will get as if passed by
> reference. =20
> 
> ed
> 
> 
> > -----Original Message-----
> > From: John Havlicek [mailto:john.havlicek@freescale.com]=20
> > Sent: Thursday, June 29, 2006 7:32 AM
> > To: Eduard.Cerny@synopsys.COM
> > Cc: john.havlicek@freescale.com; piper@cadence.com;=20
> > Bassam.Tabbara@synopsys.COM; Eduard.Cerny@synopsys.COM;=20
> > dmitry.korchemny@intel.com; Brad.Pierce@synopsys.COM;=20
> > sv-ac@eda-stds.org
> > Subject: Re: [sv-ac] 928 Proposal Updated
> >=20
> > Hi Ed:
> >=20
> > I think that sequence, property, and void arguments, as well
> > as untyped, are passed by substitution.
> >=20
> > For other typed arguments, I think that we need to use the=20
> > current LRM mechanism, which applies the assignement rules.
> > I think of this like having an implicit wire for the formal
> > argument in the declared sequence or property and assigning
> > the actual argument expression to that wire.  As a result,=20
> > the assignment rules for type coercion are used (e.g., truncation,
> > padding).  If the type of the actual argument expression cannot=20
> > be coerced to the type of the formal argument, then the compiler
> > should reject the code.
> >=20
> > Is this what you have in mind?
> >=20
> > J.H.