C CHIP-8 emulator

My own implementation of the CHIP-8 emulator, based on the "Guide to making a CHIP-8 emulator", written by Tobias V. Langhoff.

Build

To build the emulator, run following commands sequentially in the main directory:

mkdir build
cd build
cmake ..
make

Run

To run the emulator, run following command in the build directory:

./chip8 ../programs/name-of-program.ch8

Implementation status

• Test adding a instruction to memory and reading it out in the run() function
• Add SDL library support to CMakeLists
• Create macro's to fetch first, second, third and forth nibbles of instruction
  • Inline functions are probably better, but let's do a define as an exercise
• Look into how to read CHIP8 programs in this C interpreter
  • Look if program really is in memory at correct place.
  • Can you read first instruction correctly now (is it the first instruction of the IBM logo program?)
  • Can we correctly handle possible failures when reading the program? How to catch this? (Now we simply do a return;)
• Implement JUMP 1NNN instruction_get- Make generic graphics layer so SDL can be replaced with any other graphics library
  • Will be handy if we port to ESP32
• Get rid of nvim not found warnings/errors
• Make LOG macro's to do better debugging.
• Make dummy programs to call subroutines and return from them
  • You can do this with printf '\xde\xad\xbe\ef' > deadbeef.ch8
• Implement 6XNN instruction.
• Make implementation for instruction_get() function that gives back callback to instruction to execute;
• Moved all instruction to individual functions in instruction.c.
• Generate debug information:
  • Write PC
  • Write instruction
  • Write out all nibbles (to see that they're read correctly)
• Make debug function to print out VX registers.
• Implement 3XNN, 4XNN, 5XY0, 9XY0 and ANNN.
• Implement instruction 0NNN (do not implement) and 7XNN
• Add README.md.
• Check what happens if program is given as input that does not exist.
  • Also cleaned up read.c/read.h.
• Format code and start using formatter.
• Implemented FX29 instruction.
• [work-in-progress] Implement DXYN.
  • test edge of screen edge cases
  • try unsetting pixels
  • revisit where I should apply the image width and height scaling: now logic is in sdl and in interpreter
    • I would change the pixel drawing to a rectangle drawing
  • segmentation fault when testing 2 DXYN functions
  • is BIT macro well implemented?
• Refactor all NIBBLE macro's to inline functions
• Implement FX55 and FX65.
• [work-in-progress] Test 8XYx instructions.
• [work-in-progress] Implement 8XY6 and 8XYE.
  • Implement.
  • Test.
• Run cmake differently so the compile_commands.json is always generated at the correct place
  • I need to revise my cmake command
• Find a system to efficiently parse the correct instruction in instruction_get in instruction.c
• How should the program stop?
• Implement ncurses graphics library.
• Put everything in src directory.
• Add decent unit test infrastructure.