Instruction Set

---

Introduction

There are 35 instructions in the Chip8 programming language. The opcodes will contain additional information necessary to execute the instruction. This information is as follows: X represents register VX, Y represents register VY, N represents a 4-bit immediate value, NN represents an 8-bit immediate value, NNN represents a 12-bit immediate value.

Instruction Set Table

Mnemonic	Opcode	Description
CLS	00E0	Clear Screen
RET	00EE	Return from Subroutine
OEXE	0NNN	Execute machine language Subroutine at NNN. Deprecated
JUMP	1NNN	Jump to Address NNN
EXE	2NNN	Execute Subroutine at NNN
SEI	3XNN	Skip next instruction if the value in register VX equals the immediate value NN
SNEI	4XNN	Skip next instruction if the value in register VX is not equal to the immediate value NN
SE	5XY0	Skip next instruction if the value in register VX is equal to VY
STRI	6XNN	Store the immediate value NN in register VX
ADDI	7XNN	Add the immediate value NN to register VX
COPY	8XY0	Copy the value of register VY into register VX
OR	8XY1	OR the value of register VX with the value of register VY and store in register VX
AND	8XY2	AND the value of register VX with the value of register VY and store in register VX
XOR	8XY3	XOR the value of register VX with the value of register VY and store in register VX
ADD	8XY4	Add the value of register VY to register VX. VF is set to 01 if a carry occurs, else 00
SUB	8XY5	Subtract the value of register VY from register VX and store the result in VX. VF is set to 00 when negative, else 01
RSH	8XY6	Shift register VY right one bit and store the value into VX. VF is set to the shifted out bit
SUBR	8XY7	Subtract the value of register VX from register VY and store the result in VX. VF is set o 00 when negative, else 01
LSH	8XYE	Shift register VY left one bit and store the value into VX. VF is set to the shifted out bit
SNE	9XY0	Skip next instruction if the value in register VX is not equal to the value in register VY
STR	ANNN	Store the memory address NNN in register I
BR	BNNN	Jump to address NNN offset by the value in V0
RND	CXNN	Set register VX to a randomly generated number AND'd with immediate value NN
DRAW	DXYN	Render the sprite at register I to the position (VX, VY) with N bytes of data
SP	EX9E	Skip next instruction if the key corresponding to the value of the lower 4 bits in register VX is pressed
SNP	EXA1	Skip next instruction if the key corresponding to the value of the lower 4 bits in register VX is not pressed
STRD	FX07	Copy the value in register DT into register VX
WAIT	FX0A	Wait for a keypress and store the key value into register VX
SETD	FX15	Set the delay timer to the value in register VX
SETS	FX18	Set the sound timer to the value in register VX
OFFS	FX1E	Add the value in register VX to register I
NUM	FX29	Set the value in register I to the corresponding digit sprite of the value in register VX
BCD	FX33	Generate the binary coded decimal of the value in register VX starting at the address pointed to by register I
STRM	FX55	Store the values from registers V0 to VX into memory starting at the address stored in I
LDM	FX65	Load the values in memory starting at address I into registers V0 to VX