Chip 8 on the COSMAC VIP: Instruction Index

This is a series of posts in which I analyse the Chip-8 interpreter as implemented on the RCA COSMAC VIP. They are primarily intended to be of use to anyone writing a Chip-8 interpreter for another platform. However, they will also be of use to anyone wanting to know more about the COSMAC VIP in general.

This post indexes the other posts in this series by their relevance to Chip-8 instructions. There is also a simple index.

Instruction	Description	Relevant Posts
0MMM	Calls a machine code subroutine at the address 0x0MMM	Machie Code Integration
00E0	Clears the screen	Machine Code Integration
00EE	Returns from a subroutine	Machine Code Integration Branch and Call Instructions
1MMM	Branches to the instruction at address 0x0MMM	Branch and Call Instructions
2MMM	Calls a subroutine at address 0x0MMM	Branch and Call Instructions
3XNN	Skip if VX = NN	Skip Instructions
4XNN	Skip if VX ≠ NN	Skip Instructions
5XY0	Skip if VX = VY	Skip Instructions
6XNN	Load VX with NN	Loading and Saving Variables
7XNN	Add NN to VX	Arithmetic and Logic Instructions
8XY0	Load VX with VY	Loading and Saving Variables
8XY1	OR VY with VX	Arithmetic and Logic Instructions
8XY2	AND VY with VX	Arithmetic and Logic Instructions
8XY3	XOR VY with VX	Arithmetic and Logic Instructions
8XY4	Add VY to VX, load VF with carry bit	Arithmetic and Logic Instructions
8XY5	Subtract VY from VX, load VF with carry bit	Arithmetic and Logic Instructions
8XY6	Shift VY one bit right, load VX with result, load VF with bit 0	Arithmetic and Logic Instructions
8XY7	Subtract VX from VY, load VX with result	Arithmetic and Logic Instructions
8XYE	Shift VY one bit left, load VX with result, load VF with bit 7	Arithmetic and Logic Instructions
9XY0	Skip if VX ≠ VY	Skip Instructions
AMMM	Load I with the address 0MMM	Loading and Saving Variables Indexing the Memory
BMMM	Branch to the address calculated by adding 0x0MMM to Chip-8 variable V0	Branch and Call Instructions
CXNN	Load VX with a random number from 0 to 255 ANDed with NN	Generating Random Numbers
DXYN	Draw the N byte sprite stored at the address pointed to by I on the display at location X and Y. Set VF to 0×01 if any set pixel in the sprite overwrites an existing set pixel on the display, otherwise set VF to 0×00	Drawing Sprites
EX9E	Skip if VX = current key press	Skip Instructions Keyboard Input
EXA1	Skip if VX ≠ current key press	Skip Instructions Keyboard Input
FX07	Get the current value of the timer into VX	The General Purpose Timer
FX0A	Wait for a keypress and store the value in VX	Keyboard Input
FX15	Set the timer with the value of VX	The General Purpose Timer
FX18	Set the sound timer with the value in VX	Sound
FX1E	Add value in VX to I	Indexing the Memory
FX29	Load I with address of sprite for the character in VX	The Character Set Binary Coded Decimal
FX33	Store the BCD representation of the value in VX at I, I+1 and I+2	Binary Coded Decimal
FX55	Save variables V0 through VX starting at the address in I	Loading and Saving Variables
FX65	Load variables V0 through VX from memory starting at the address in I	Loading and Saving Variables

Here is a PDF with the complete CHIP-8 Interpreter Disassembly.