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Old 11-23-2007, 07:56 AM
Kim Enkovaara
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Default Re: EDK + Modelsim simulation : Memory allocation failure

Pasacco wrote:
> The "memory allocation problem" occurred when I tried to run "Post PAR
> simulation" in Modelsim.
> SDF file size is 29MB. The system contains 12 MicroBlaze and totally
> 125 BRAMs.
> It seems that 29MB of SDF file and 12 MicroBlazes are too much for
> Modelsim.


That should not be a problem. I have simulated with Modelsim designs
that have 2+Gbyte SDFs and hundreds of big memories. And those
simulations needed about 3G of memory with Modelsim-SE.

Netlist simulations are usually quite hard to get going. Why do you even
need them? RTL-simulations + STA should usually be enough, unless
synthesis bug is suspected or some error in STA scripts.

At ASIC side netlist simulations are more common, but there the errors
also cost millions of dollars. I consider netlist simulations to be
aid for STA script verification, if formal tools for that are not
available for the user.

> If anyone has experience to "simulate (relatively) large system",
> please let me know.


You could try without vopt, just add -novopt to the vsim command line.
It seems that vopt is running out of memory, and that is the
optimizer before simulations. I have been more successful with the old
-fast flow especially for big netlists.

--Kim
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