Thoughts on DMA
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 […]
Category: Design Log
Moved development to “the cloud”
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 […]
Disassembler working!
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 […]
Simulator Signal Graph
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 […]
Thoughts on exceptions
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 […]
Stack instructions complete
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 […]
Interrupts are working!
Spent a bunch of today working on microcode and a unit test for interrupts, and got it all working! There are now 8 working interrupt lines that support separate ISRs for each and have a priority system, and there’s a […]
Instruction implementation mostly complete!
Finished off the rewrite of the microcode assembler yesterday, the new one has now taken over as the reference implementation and is the primary microcode assembler used by the simulator. I still want to implement some optimization features later on, […]
Microcode assembler work
I’ve spent a bit of time over the past couple of months re-implementing the microcode assembler from scratch. The original microcode assembler was thrown together to save me from typing 64 ones and zeroes for every word of microcode (which […]
Microcode getting close to complete
I implemented the microcode for the 16 bit, 8 bit low, and 8 bit high variants of AND, OR, and XOR this evening, which went smoothly (if a bit tediously). At this point 47 instructions are implemented in microcode, and […]