Glossary #

This page list some common terms used in the documentation, in CHIP-8 and in #chip-8 on the EmuDev Discord. I do not claim these are the official definitions, just that this is hopefully helpful to better understand the texts and debates.

This is just a start, more definitions will follow.

COLLISION #

Whenever a draw operation (Dxyn) erases a formerly drawn pixel on the screen as a result of the XOR operation, this is called a collision. Games use this e.g., to detect when a player collides with an obstacle. The only exception is MEGA-CHIP in its megaon mode, where a drawn pixels color is instead compared to the collision color.

COSMAC #

The name of the CPU the first CHIP-8 was designed for. It stands for Complementary Symmetry Monolithic Array Computer and is a 70s era 8 bit microprocessor with 16 registers (probably the reason why CHIP-8 has 16 registers too).

COSMAC VIP #

The COSMAC VIP was a computer by RCA, released in 1977 and it came with a CHIP-8 interpreter printed in the manual. This interpreter is what this reference refers to as the original CHIP-8 interpreter.

IPF #

Instructions Per Frame, the number of instructions executed per frame. For generic emulation the recommended approach is to handle timers and input, then execute that IPF number of instructions in a tight loop, then update the visible screen.

PIXIE #

The CDP1861 video chip in the COSMAC VIP that shaped CHIP-8 by its limited resolution of 64x32 basically square pixels.

Sprite #

A graphical object that can be drawn on the screen. This is kinda misleading, since it’s not related to hardware sprites, but in CHIP-8 context just means a bit pattern drawn by the Dxyn opcode. Still it is so widely used that it is basic terminology in CHIP-8 documentation.