chip8compilerjs's Introduction

CHIP-8 Compiler

This is a CHIP8 Compiler developed using JavaScript. It allows you to write code, compile, and see it in the emulator afterwards.

Usage

Click the Compile button to compile the code. Click Start or Step to run your code in the emulator. You can click Stop to stop the emulator, and you can click Reset to reset it. Clicking the Save button on the left will allow you to download the compiled binary file.

Language

Insturction names and descriptions are taked from Cowgod's Chip-8 Technical Reference v1.0.

Opcode	Instruction	Description
0nnn	SYS addr	Jump to a machine code routine at nnn.
00E0	CLS	Clear the display.
00EE	RET	Return from a subroutine.
1nnn	JP addr	Jump to location nnn.
2nnn	CALL addr	Call subroutine at nnn.
3xkk	SE Vx, byte	Skip next instruction if Vx = kk.
4xkk	SNE Vx, byte	Skip next instruction if Vx != kk.
5xy0	SE Vx, Vy	Skip next instruction if Vx = Vy.
6xkk	LD Vx, byte	Set Vx = kk.
7xkk	ADD Vx, byte	Set Vx = Vx + kk.
8xy0	LD Vx, Vy	Set Vx = Vy.
8xy1	OR Vx, Vy	Set Vx = Vx OR Vy.
8xy2	AND Vx, Vy	Set Vx = Vx AND Vy.
8xy3	XOR Vx, Vy	Set Vx = Vx XOR Vy.
8xy4	ADD Vx, Vy	Set Vx = Vx + Vy, set VF = carry.
8xy5	SUB Vx, Vy	Set Vx = Vx - Vy, set VF = NOT borrow.
8xy6	SHR Vx Vy	Set Vx = Vx SHR 1.
8xy7	SUBN Vx, Vy	Set Vx = Vy - Vx, set VF = NOT borrow.
8xyE	SHL Vx Vy	Set Vx = Vx SHL 1.
9xy0	SNE Vx, Vy	Skip next instruction if Vx != Vy.
Annn	LD I, addr	Set I = nnn.
Bnnn	JP V0, addr	Jump to location nnn + V0.
Cxkk	RND Vx, byte	Set Vx = random byte AND kk.
Dxyn	DRW Vx, Vy, nibble	Display n-byte sprite starting at memory location I at (Vx, Vy), set VF = collision.
Ex9E	SKP Vx	Skip next instruction if key with the value of Vx is pressed.
ExA1	SKNP Vx	Skip next instruction if key with the value of Vx is not pressed.
Fx07	LD Vx, DT	Set Vx = delay timer value.
Fx0A	LD Vx, K	Wait for a key press, store the value of the key in Vx.
Fx15	LD DT, Vx	Set delay timer = Vx.
Fx18	LD ST, Vx	Set sound timer = Vx.
Fx1E	ADD I, Vx	Set I = I + Vx.
Fx29	LD F, Vx	Set I = location of sprite for digit Vx.
Fx33	LD B, Vx	Store BCD representation of Vx in memory locations I, I+1, and I+2.
Fx55	LD I, Vx	Store registers V0 through Vx in memory starting at location I.
Fx65	LD Vx, I	Read registers V0 through Vx from memory starting at location I.

Dependencies

Resources

License

The source code is provided under MIT License.

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chip8compilerjs's Issues

Display should show something

After initializing the emulator it should run the logo application. Loading programs should both reset and load.

Keyboard missing

Wrong code flow

I put the following code on emulator to test it:

LD V0 0x5

SE V0 0x5 //skip if vx equal kk
JP L1
JP L2

L1:
.... LD V1 0x1
.... JP L1`

L2:
.... LD V1 0x2
.... JP L2

In this code, only the loop code starting at the "L2" label would be executed, but that is not what is happening, SE is not skipping the next instruction, causing L1 to always be executed.

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