RE: [ethmac] operator precedence

[Illan Glasner <IGlasner@mrv.com>]

   Hi,

	 Of course all depend on "writing-style" etc etc
etc however it
can;t hurt so you might want to try this , I don;t gurrenty nothing
as just
tried it on small file I wrote quickly and also inculde the example
you
gave.

-----------------

This is the file I just tried it on :

daria[iglasner-~]> cat a.v 
wire d = &a ;
wire e = |b && &c ;
wire f = |dc0 && &c ;
wire g = |c1b && &c ;
wire h = |c12fg && &c ;
wire i = |c12fg || &c ;
wire m = |c12fg || &c && d || g;

if( |PauseTimer[15:0] & RxFlow) 

---------------

I than apply a script I just wrote now and this the result :

daria[iglasner-~]> awk -f awk.f a.v
wire d = (&a) ;
wire e = (|b) && (&c) ;
wire f = (|dc0) && (&c) ;
wire g = (|c1b) && (&c) ;
wire h = (|c12fg) && (&c) ;
wire i = (|c12fg) || (&c) ;
wire m = (|c12fg) || (&c) && d || g;

if( (|PauseTimer[15:0]) & RxFlow)

-------------

if you "like it" all you miss is the awk.f and here it is :

daria[iglasner-~]> cat awk.f 

{
for (i=1;i<=NF;i=i+1) {
   len=length($i)
   symb0=substr(($i),1,1)
   symb1=substr(($i),2,1)
   if (((symb0=="|") || (symb0=="&")) &&
!((symb1=="|") || (symb1=="&"))  &&
(len>1)){
      $i="("$i")"
      }
   }
print $0
}


Enjoy and hopefully it will be of some use.

if there is any particular case it don;t solve you can send it and I
will
try to see what I can do to help assuming it is something simple as
I'm not
an expert in scripts.

have a nice weekend

   Illan



-----Original Message-----
From: zjli@technologist.com
 [mailto:zjli@technologist.com]
Sent: Friday, October 11, 2002 4:51 PM
To: igorm@opencores.org; ethmac@opencores.org

Subject: RE: [ethmac] operator precedence


The problem should not be very serious. It is less serious if we know
what
simulation/synthesis tools interpret these 
expressions as intended.

Most tools should agree with the future Verilog LRM because it also
agrees
with the old Verilog LRM from OVI. The LRM from 
OVI does not show "~|" in the precedence table, and it also
says the
precedence order is the same as in C. In C, unary 
operators always have higher precedence than binary operators. So,
only new
tools developed after 1995 might be different.

It is still good to know the possibility that this MAC core might
behave
differently if you use different tools.

At least, we should add parentheses when we accidentally see these
problems.
When we debug problems, it might help to 
remember this issue.

Thanks,
Jeff

----- Original Message ----- 
From: "Igor Mohor" <igorm@o... > 
To: <ethmac@o... > 
Date: Fri, 11 Oct 2002 18:46:31 +0200 
Subject: RE: [ethmac] operator precedence 

> 
> 
> Sorry, 
> 
> but at the moment I don't have time to go through all files and
add 
> parentheses as you suggested. 
> 
> Regards, 
> 	Igor 
> 
> 
> 
> > -----Original Message----- 
> > From: owner-ethmac@o...  
> [mailto:owner-ethmac@o... ]On 
> > Behalf Of zjli@t...  
> > Sent: 11. oktober 2002 21:28 
> > To: zjli@t... ; ethmac@o...  
> > Subject: Re: [ethmac] operator precedence 
> > 
> > 
> > The precedence of unary "|" is not completely
clear in IEEE 
> 1364-1995 
> > and IEEE 1364-2001. Under the section title "Binary
operator 
> > precedence", "|" is listed only once while
"+" and "-" are 
> listed 
> > as binary 
> > and unary separately. I took this "|" as both
unary and binary 
> > because "|" and "~|" are listed as
having the same precedence, 
> > and "~|" is always unary. 
> > 
> > The draft LRM for the future Verilog standard clearly
listed 
> that 
> > all unary 
> > operators have higher precedence than all binary operators. 
> > 
> > It is a good idea to add parentheses in such cases. 
> > 
> > ----- Original Message ----- 
> > From: zjli@t... 
> > To: ethmac@o... 
> > Date: Wed, 9 Oct 2002 22:40:41 -0100 
> > Subject: [ethmac] operator precedence 
> > 
> > > 
> > > 
> > > In eth_receivecontrol.v, "if(|PauseTimer[15:0] & 
> RxFlow)" is 
> > > currently 
> > > used for computing Divider2. Apparently, it meant 
> "if((|PauseTimer 
> > > [15:0]) & RxFlow)" but it could mean 
> "if(|(PauseTimer[15:0] 
> > > & RxFlow))" 
> > > according to both IEEE 1364-1995 and IEEE 1364-2001. 
> > > 
> > > I am curious what tools did not agree with my 
> interpretation of 
> > > IEEE 
> > > standards. 
> > > 
> > > Thanks, 
> > > Jeff 
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