GaLaKtIkUs=99 wrote:
> Rewrite the whole libraries, which model Xilinx primitives for all
> Xilinx FPGA/CPLD families and all speed grades?

Why not just rewrite the ones you need, instead of ALL of them?

Mike Treseler wrote:
> GaLaKtIkUs� wrote:
> 
>> I wanted to use Icarus but I was confronted to a big problem (as a user
>> of Xilinx): in the simlation libraries there are specify blocs and
>> Icarus verilog doesn't support them.
> 
> Could you write your own code
> and not use the libraries?

Ugh! There is no need for that. As I said already on this thread,
Icarus Verilog will (should) parse and ignore specify blocks and
the end result is a perfectly good simulation. All you miss in this
context is back-annotation support.

Any other problems simulating with Xilinx models should be posted
in the bug tracking database. I *will* fix such bugs, because I
do Xilinx work with Icarus Verilog regularly.

-- 
Steve Williams                "The woods are lovely, dark and deep.
steve at icarus.com           But I have promises to keep,
http://www.icarus.com         and lines to code before I sleep,
http://www.picturel.com       And lines to code before I sleep."

Static Timing Analysis.

It's nearly impossible to prove that a design will work with
simulation.  Static Timing Analysis is a simulation-less proof
mechanism.  The tool uses clock periods and setup and hold times and
propagation delays of the hardware to prove it a design will meet a
specified timing.

A digital design flow should go basically like this:
1=2E Specify and make list of features.
2=2E Implement RTL.
3=2E Write functional simulations to test features exhaustively.
4=2E Test features.
5=2E Write design constraints.
6=2E Synthesize.
7=2E Run Static Timing.
8=2E Do timing fixes if necessary, go back to step 4.
9=2E Tape out or do whatever you need to do with your complete design.

The point is you should never need to run timing sims.  That said, I've
never worked on a chip that didn't need them.  All I can say is that
you almost can't guarantee a circuit to be working through timing gate
sims.

-Arlen
GaLaKtIkUs=99 wrote:
> Mike Treseler wrote:
> > GaLaKtIkUs=99 wrote:
> > > Rewrite the whole libraries, which model Xilinx primitives for all
> > > Xilinx FPGA/CPLD families and all speed grades?
> >
> > No.
> > Leave the primitives to synthesis.
> > Leave the timing to STA.
>=20
> STA?
>=20
> >=20
> >     -- Mike Treseler

Mike Treseler wrote:
> GaLaKtIkUs=99 wrote:
> > Rewrite the whole libraries, which model Xilinx primitives for all
> > Xilinx FPGA/CPLD families and all speed grades?
>
> No.
> Leave the primitives to synthesis.
> Leave the timing to STA.

STA?

>=20
>     -- Mike Treseler

GaLaKtIkUs� wrote:
> Rewrite the whole libraries, which model Xilinx primitives for all
> Xilinx FPGA/CPLD families and all speed grades?

No.
Leave the primitives to synthesis.
Leave the timing to STA.

    -- Mike Treseler

Rewrite the whole libraries, which model Xilinx primitives for all
Xilinx FPGA/CPLD families and all speed grades?
:-S


Mike Treseler wrote:
> GaLaKtIkUs=99 wrote:
>
> > I wanted to use Icarus but I was confronted to a big problem (as a user
> > of Xilinx): in the simlation libraries there are specify blocs and
> > Icarus verilog doesn't support them.
>
> Could you write your own code
> and not use the libraries?
>=20
>   -- Mike Treseler

GaLaKtIkUs� wrote:

> I wanted to use Icarus but I was confronted to a big problem (as a user
> of Xilinx): in the simlation libraries there are specify blocs and
> Icarus verilog doesn't support them.

Could you write your own code
and not use the libraries?

  -- Mike Treseler

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Jim Granville wrote:
> Stephen Williams wrote:
>> GaLaKtIkUs� wrote:
>>> I wanted to use Icarus but I was confronted to a big problem (as a user
>>> of Xilinx): in the simlation libraries there are specify blocs and
>>> Icarus verilog doesn't support them and there are no shoft term plans
>>> to support them. Great was my deception (as open source enthusiast) but
>>> now I'm obliged to use a commercial simulator.
>>
>>
>> It doesn't matter. The specify blocks are ignored and simulation
>> works just fine. You will not be able to do back-annotated post-
>> par timing simulations, but functional simulations work just fine.
>>
>> I (and my day job co-workers) use Icarus Verilog for Xilinx work
>> all the time.
> 
>  Interesting - can you give some comments on the relative speed /
> reliability /size of the present Icarus release ?

I can say with certainty that a licensed Modelsim simulator is
faster. Others will be able to say how much faster. I do image
processing in a 1/3 full XC2V3000 w/ SDRAMS, and I can simulate
plausible jobs. Sometimes I even do simulations on my 1.3GHz
Powerbook G4:-)

Now when you say "present Icarus release", there are the current
snapshots and there is the v0.8 stable branch. The stable branch
is a little faster in some cases, but is not as complete in others.
The stable release is "stable", but the snapshots are getting the
bug fixes and new features.

- --
Steve Williams                "The woods are lovely, dark and deep.
steve at icarus.com           But I have promises to keep,
http://www.icarus.com         and lines to code before I sleep,
http://www.picturel.com       And lines to code before I sleep."
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Stephen Williams wrote:
> GaLaKtIkUs� wrote:
>>I wanted to use Icarus but I was confronted to a big problem (as a user
>>of Xilinx): in the simlation libraries there are specify blocs and
>>Icarus verilog doesn't support them and there are no shoft term plans
>>to support them. Great was my deception (as open source enthusiast) but
>>now I'm obliged to use a commercial simulator.
> 
> 
> It doesn't matter. The specify blocks are ignored and simulation
> works just fine. You will not be able to do back-annotated post-
> par timing simulations, but functional simulations work just fine.
> 
> I (and my day job co-workers) use Icarus Verilog for Xilinx work
> all the time.

  Interesting - can you give some comments on the relative speed / 
reliability /size of the present Icarus release ?

-jg

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GaLaKtIkUs� wrote:

> I wanted to use Icarus but I was confronted to a big problem (as a user
> of Xilinx): in the simlation libraries there are specify blocs and
> Icarus verilog doesn't support them and there are no shoft term plans
> to support them. Great was my deception (as open source enthusiast) but
> now I'm obliged to use a commercial simulator.

It doesn't matter. The specify blocks are ignored and simulation
works just fine. You will not be able to do back-annotated post-
par timing simulations, but functional simulations work just fine.

I (and my day job co-workers) use Icarus Verilog for Xilinx work
all the time.

- --
Steve Williams                "The woods are lovely, dark and deep.
steve at icarus.com           But I have promises to keep,
http://www.icarus.com         and lines to code before I sleep,
http://www.picturel.com       And lines to code before I sleep."
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