Putting It Together

The complete cycle:

Main loop:

500 Hz is standard. Some games need 700 Hz to feel right. Make it configurable.

Testing:

• BC_test.ch8: tests core opcodes.
• chip8-test-suite (Timendus): comprehensive ROM test.
• Run famous games: Pong (PONG), Tetris, Space Invaders.

Common issues debugging:

• Sprites disappear: didn't wrap coordinates.
• Game runs too fast/slow: CPU rate misconfigured.
• Garbage on screen: not clearing display, or DRW XOR bug.
• Keys not detected: check key mapping.
• Crashes on RET: stack underflow (forgot to push on CALL).

Quirks (different per implementation):

• Shift opcodes: shift VX (modern) or VY then to VX (original).
• I increment in FX55/FX65: yes (original) or no (modern).
• Display wait: some games expect DRW to wait for vblank.

Have a quirks config so different ROMs can be played.