For support of an old product, we may need to modify a Xilinx Spartan 3 FPGA. This was originally designed in VHDL with Modelsim Designer and ISE 9.2, both no longer available. New Vivado versions do not seem to support Spartan 3.
What are the current options for making changes to a Spartan 3 design?
Facts are stubborn, but statistics are more pliable.
Thanks for that link! We do have a very old ISE 9.2 installation file, but I was affraid it would not run on newer OS'es and that the registration was no longer possible. The OS could be solved by using a VM, but not the registration. Your link shows you can still obtain a registration ID for 9.2.
Aparantly there even is a 14.7 version for Windows 10 that supports older Spartan devices. So this may be an option as well.
The original design made use of Modelsim Designer. I think mainly for the simulator? Do the ISE 9.2 and 14.7 installations include a decent simulator?
By doing just a little every day, you can gradually let the task
The 14.7 version for Windows 10 uses the 'Windows subsystem for Linux' which I believe is a VM built into Windows. I've never used it. There is a minor patch that allows the 'regular' 14.7 version to run on Windows 10 without the need for the Linux subsystem.
Here's a link to a video that shows how to do that:
I've only ever used the simulator (ISim) included with ISE so I'm not qualified to say if it is 'decent'.
If you have Modelsim, I believe ISE can use it by setting the Project-Design properties in ISE Project Navigator but again I've never done that so I can't say how well it works.
The WIN10 version for 14.7 is just a virtual machine. Since I run Linux and Windows only in a virtual machine, I simply continue to use my WIN7 virtual machine with VMware. VMware is transparent enough to handle the Xilinx download cable via USB.
A virtual machine in a virtual machine is probably asking for too much.
I vaguely recall that 9.2 was somewhat nasty. I evaded to 10.something, the latest version that still supported the original Virtexes. One point was that ISE had some invisible caches. You could get error messages involving variables that were no longer part of the project since a week. That could be invoked by copying the entire project to somewhere else. It was much safer to just copy the sources and setup the project completely anew.
I only used Modelsim, Questa sometimes. And Silos before that. :-)