Notes about tool compatibility of the LEON2-FT VHDL model:
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Modelsim compatibility (Aug 2006):
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The model does not compile with Modelsim versions 6.1 (6.0 ?). Compilation
fails with an unexplained error in iu.vhd. Any previous version (5.x) can be  
used instead. Problem disappeared with Modelsim 6.2a (June 2006), but 
loading of the simulation with 6.2a in fails for certain model configurations, 
when using the vopt flow (which is default now), due to a bug related to the
conditional generate statements, which are extensively used in the model. 
Workaround is using the -novopt command-line option, or adding the line
VoptFlow = 0 to modelsim.ini. Mentor says the bug is fixed in release 6.2b.

Synopsys VHDL compiler/Presto compatibility:
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February 2006:
With Synopsys version X-2005.09, the Presto compilation error mentioned below has disappeared.
The model can therefore be compiled without modifications, provided Presto is available.
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Note that in an article from June 2004, Synopsys has also reported a bug in VHDL compiler 
related to bussed clocks, and this is apparently the reason why the feature has been 
disabled in VHDL compiler. However, the article says that a way to re-enable the feature 
can be provided on-request by Synopsys FAE. https://solvnet.synopsys.com/retrieve/012168.html
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There is no further evidence of wrong netlists being produced by either VHDLC or Presto.


June 2005:
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An incompatibility of the LEON2FT model with recent versions (e.g. 2004.06-SP2) of Synopsys DC 
has been reported by users. It is not possible any more to elaborate LEON2FT with the old VHDL 
compiler. Using PRESTO (setting variable hdlin_enable_presto_for_vhdl = true), the compilation 
also fails.
In addition, some users have reported cases where compilation passed, but produced wrong 
netlists. In conclusion, ESA STRONGLY DISCOURAGES USING PRESTO FOR LEON. As a workaround, 
switching back to an older Synopsys version is recommended (2003.06-SP1 has been reported 
to work correctly).


Note for FPGA compilation (18. June 2004):
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LEON2FT in all its current versions is not synthesisable with Xilinx XST.
If you want to synthesise LEON2 for Xilinx with this tool, please download
one of the leon2-xst versions from www.gaisler.com