Paging was implemented way back near the beginning of the project, but page faults hadn’t been implemented yet. This seemed like a good next thing to work on, so I started looking into it today. I last looked at this […]
I started working on DMA support and got it most of the way there, but then some of my tests were acting weird. After digging into things with GTKWave a bunch it looked like both 16-bit loads and stores were […]
When I first set up the test framework, I just had iverilog running the CPU directly, as everything happened inside that and there was no reason to add another layer of complexity. Once I needed to test interrupts however, I […]
I’ve been reading through Linkers and Loaders for the last couple months, and my brain is very full with toolchain stuff so I figured I’d think about hardware again for a little bit. I think DMA will probably just be […]
Quick update today, I’m in the process of moving off of my current laptop (a MacBook Late 2008) and figured I should look at moving the development/test environment into the cloud (senCloud that is) since there’s no real reason to […]
Got back up to speed on the project recently after some time away (pandemic), and picked up where I left off. I’d meant to make the jmp instructions PC-relative originally, but ended up implementing them as absolute temporarily until I […]
Looking into the toolchain more, the next step after the assembler seemed to be a disassembler. LLVM handles a lot of the details of this using the same data tables created for the assembler, so it seemed like it wouldn’t […]
I took a break for a few days from working on the design itself, to work on a tool to generate a graph of the simulator signal flow. The signal flow in parts of the CPU is getting complicated enough […]
The next thing to implement is going to be exceptions, or traps, or faults, I haven’t really decided what to call them yet. We’ll need them for syscalls, page faults, breakpoints, and probably things I haven’t realized yet. My current […]
After a year away from the project (we adopted a puppy and then there’s been a pandemic), I got back into it today and picked up where I left off in 2019. I’d realized that the stack instructions had been […]