Added realistic propagation delays to alu4 and finished the RAM delays, fixed a couple timing issues and tests all pass at 25MHz and 33MHz now. Am going to leave the clock at 25MHz for the time being, as that’s the […]
Worked on sub8.ab some more, it now works and passes all its unit tests. Also wrote some extra tests for this, to be more confident in its workingness. Next step will be to finally finish CALL and RETURN. I started […]
Worked on pop16.pc more, it now works and passes all of its unit tests. Am still working on sub8.ab, that one still doesn’t work.
Worked on pop16.pc microcode and sub8.ab microcode a bunch. Didn’t get to a point where either works yet.
Figured out the register flow requirements for pop16.pc, and documented it in a diagram. Next step will be to implement the unit test and microcode for it.
Implemented ‘include’ functionality in the microcode generator so that instructions like call (which is really just push16.pc then jmp) can be written as an include, rather than having to copy/paste the contents of those other instructions and maintain two copies.
Implemented CALL instruction, which is now working. Extended the microcode generator so it will now generate a mapping file to translate from a control store address to an instruction name (and step within that instruction), which can be loaded into […]
Refactored all the microcode instructions and their unit tests so that PC now equals the instruction currently being executed, and not the memory location after that. Implemented push16.pc and its unit test and everything works as intended. Next step will […]
Reworked PUSH into push8.imm and push8.? (for future implementation of other non-immediate push8s). Implemented push16.imm and push16.? including their unit test and register transfer diagram. Started working on push16.pc, but ran into an issue where PC is incremented within FETCH, […]
Finished implementing PUSH, including the unit test for it. All seems to be working now, and I fixed a lot of bugs related to RAM while working on this, as this is the first use of RAM in the system. […]