Which free VHDL simulator can I use?

Posted Tue, 2011-06-21 14:24

Sigasi Pro is not a simulator. If you don't have a VHDL simulator yet, we would recommend the following simulators. You can download them free of charge.

Simulator Comment Download from Windows Linux Mac OSX
Aldec Active-HDL, Student Edition Students only Aldec Download page Yes No No
ModelSim Altera Starter Edition Only Altera FPGAs Altera Quartus Web Edition Yes Yes No
ISim Only Xilinx FPGAs Xilinx Webpack Yes Yes No
Simili SymphonyEDA website Yes Yes No
GHDL limited features; only VHDL-93 GHDL website Yes Yes Yes

We have not had great results with FreeHDL or with Green Mountain VHDL. It seems that these projects may have been terminated.
GHDL on Mac OSX uses Wine, but works without problems.

Comments

ISim verse Aldec

by Anonymous - 2012-06-04 02:18

I compared the free version of ISim (comes with Xilinx Web Pack) with Aldec (comes with the non free Altium Designer). I ran the same test VHDL design simultaneously on my desktop PC for 5 minutes.
The ISim simulator advanced the simulation time to 7187.8 uS, while the Aldec simulator only to 78.5 uS.

is this representative?

by philippe.faes (Sigasi) - 2012-10-08 16:58

Such short test is not necessarily a good indication of the performance of those tools. There is no way to tell if one is really 100 times slower than the other. For example, the startup time might be a lot slower, but the actual simulation time might be faster. Benchmarking compilers (or in this case: simulators) is an entire field of research in its own.

Some steps to help get better results: You need to run multiple test, which are representative for what the average design will look like. One key element is that you need BIG designs. Also, you should make sure that there are no external influences on your computer (network activity, other processes running, etc).

That said, my hunch is that you are right that Aldec's simulator is a lot better than ISim. It is Aldec's core business to build simulators and for Xilinx ISim is not really an important product.

GHDL on Mac OS X

by dio gratia - 2011-07-16 03:57

There is a current Mac OS X version of GHDL mcode version available on the ghdl.fr web site. Download includes an installer requiring administrative privilege to save to /local/bin. It includes instructions and scripts to build from source. Currently supports Mac OS X versions 10.5 and 10.6 on Intel (i386). The mcode version is direct code generating and only supports i386 currently.

What about Simili from Symphony EDA?

by trondd - 2011-06-21 15:17

What do you think about Simili from Symphony EDA? They also provide a free (as in beer) VHDL simulator for Windows and Linux.