Simulating global and local memory on OVP

The Simons' BASIC start-up screen

The Simons’ BASIC start-up screen (Photo credit: Wikipedia)

Had a good meeting with my PhD supervisor today: he was in London – I didn’t have to make a flying visit to York.

So the next steps with my OVPsim Microblaze code is to model global and local memory – by default OVPsim treats all memory as local, mapping the full 32-bit address space and sparsely filling that as needed. I have imposed an additional constraint of only mapping a few pages, but these are still all “local”: so while the code takes time to execute, what is in effect, a FIFO page replacement algorithm, there is no time for page loads.

The way round this seems to be to build my global memory as a memory-mapped peripheral device – I can then impose time delays on reads and writes.

But I suppose I am writing this blog instead of writing that code…