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… Read More Simulating global and local memory on OVP
I have been struggling with a problem with my Microblaze simulation on OVPsim all week. I have been trying to make a start on implementing a simple demand paging system and to trigger the hardware exception that the Microblaze CPU manual says should happen when you either try to read from a mapped page that… Read More Why I owe @slugonamission a (or several) large drink(s)
Having successfully written a couple of simple virtual memory mappings I now want to write the exception handling code that will allow me to swap mappings in and out – so I did this: I expected that the marked line would raise a hardware exception as a TLB miss and I’d be taken to the… Read More Latest Microblaze puzzle
Tonight I finally managed to get the code and the sequencing right to not just boot the Microblaze simulation, but to turn on the MMU. But I was puzzled as to why, as soon as I had done that, the execution breaks with a segmentation fault and appeared to be executing code I had not… Read More Of course turning on the MMU breaks your code!
I have had a frustrating few days trying to get to grips with two new pieces of the technology: the OVP simulator and the Microblaze processor. Finally I think the fog is beginning to clear. But that also reveals just what a task I have in front of me: namely to write some kernel code… Read More Scale of the task
Paging and virtual memory is at the heart of just about any computing device – more complex than a DVD player – we use everyday. Paging is the memory management system based on the idea that we can divide the real memory of our computer into a sequence of smallish (typically 4,096 bytes) of “page… Read More After paging?
Update: I have truncated this article for now (20 December) as there was an error in my LRU software that made LRU look like a much better performer than it really was. I’ll update this with the correct data shortly…. In 1966 László Bélády published “A study of replacement algorithms for virtual storage computers”,… Read More In the steps of László Bélády