8-bit CPU.

Features:

• Flexible microcode (up to 4096 microinstructions).
• Each microinstruction can encode multiple operations. All executed at one tick.
• Microcode ROM has main and aux pages.
• Can address up to 256KiB of RAM.
• Segmented memory: 16-bit offset and 8-bit segment form a 18-bit address.
• ALU with add, sub, and logic operations.
• Flags and conditional jumps.
• 16-bit Instruction Pointer.
• 16-bit Stack Pointer.
• +/-1 circuit for IP and SP.
• Two 16-bit general registers D and P formed by four 8-bit registers A, B, X and Y.

To build microassembler run

cmake -B cmake -B cmake
make -C cmake

Then compile microcode for brainfuck

cmake/mas mas/examples/brainfuck/mc.mas

Now CPU can execute brainfuck programs (, operator is not supported though).

To build Logisim circuit, run

python build.py circ

Then build the Logisim components using maven

pushd logisim-comps
mvn package
popd

Now you can run Logisim

java -jar logisim-comps/src/main/resources/logisim-generic-2.7.1.jar

Press Ctrl+O, select .circ file in the repo root dir. Select main rom & ram on the left side.

In Simulate menu enable simulation and ticks. Increase frequency since brainfuck is not very efficient. After a while you'll see "Hello World!".