Registers & Memory

CHIP-8 state:

Loading a ROM:

Programs are positioned at 0x200 (everything below was the original interpreter).

Font set: predefined 80 bytes representing characters 0-F (4x5 pixel sprites).

Loaded at 0x50. Used to display hex digits via instruction FX29.

Stack:

• 16 entries deep (some implementations 12).
• Used by CALL/RETURN.
• Overflow → undefined; emulators typically ignore or wrap.

Timers:

• Decremented at 60 Hz independent of CPU cycles.
• When sound_timer > 0: beep.
• Hardware-clocked; emulator uses real-time clock.

Endianness: all multi-byte values big-endian. First byte = high.

Wrapping: registers are 8-bit. Arithmetic wraps mod 256. VF often = carry/borrow flag.