| Tetris | Pong |
|---|---|
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CHIP-8 is an interpretted programming language developed by Joseph Weisbecker in the mid 70s and was initally used on the COSMAC VIP and Telmac 1800 8-bit microcomputers to make game programming easier. CHIP-8 programs are run using a CHIP-8 virtual machine.
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.
| 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 |
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