MDR-XY data path implemented, Load Immediate 8-bit values to A and B instructions written, add 16-bit A=A+B written, all working.
Found a bug in the datasheet of the MC10H181, fixed it and now the ALU checks out completely. Started integrating it into the CPU. Next step is to finish the MDR-XY data path so that Load Immediate instruction can be […]
Verilog transcription of ALU is almost complete, but seems to be malfunctioning in the carry logic of the second bit. Will be using MC10H181 w/ MC10H179 CLA generator.
Started working on the design of the ALU system and transcribing internal diagrams from datasheets into Verilog.
Added decode support for ROM/RAM/device memory, got everything working so that now an instruction is fetched from ROM at startup and is jumped to in microcode. Started work on the X/Y registers, and started work on a microcode generator so […]
Got the part of the design that’s been diagrammed so far converted into Verilog and working. Now it fetches instructions (from a constant right now, not ROM or RAM yet) and does jumps to their location in microcode.
Started the logical diagram and the microcode layout.
Spent the weekend reading Bit-Slice Microprocessor Design, which clarified a lot of the parts of a microcoded CPU that I’d previously been fuzzy on.
Started putting the basic ideas and architecture for ECLair together.