chip8 | A chip8 emulator | Emulator library

I'm new to Rust, I have a file structure like this

• main.rs

• chip8.rs

• chip8_gui.rs

I added a unit test in main.rs and a unit test in chip8.rs (a simple assert_eq!(2,2)) but it only finds the test in main.rs. Why? I am trying to test a private function of chip8.rs.

I am new to emulation and figured writing a CHIP-8 interpreter would get be started. However, I am facing an issue. When running a game, like Brix for example, it draws the game no problem (the paddle, etc.) but, after it is done, it just gets stuck in a loop of 0x3000 and after that, a jump instruction that jumps back to the 0x3000. It is clear that 0x3000 is false and that is why it is looping, but I can't figure why that is for the life of me.

Screenshot of the game and the Chrome devtools console (the game is Brix, taken from here): https://i.stack.imgur.com/a0wNM.png

In that screenshot, in the console, you can see the 0x3000 is failing and going to a jump, and that jump goes back to 0x3000, and the cycle repeats. This happens with most, if not all games. I suspect is has something to do with the delay timer, since 0x3000 is checking for v0 === 0, but it fails, and goes to the jump instruction.

Here is my main CHIP-8 class:

I am writing a simple chip8 emulator.

I have a value called programCounter(PC).

The problem is that once I return from the Instruction1( which modifies PC), PC returns to the value it was before being modified by the method.

Before Instruction1 assigns to PC, the value of PC is 203.

After Instruction1, the value of PC is (0x0NNN & 0xFFFE).

By programCounter++, it return to 203 than increments.

While building a chip-8 emulator, I ran into the problem where the 2 main sources of chip-8 information seem to differ which has implications for the whole chip-8 interpreter.

On the one side we have wikipedia, which under the opcode FX65 tells us that

"Fills V0 to VX (including VX) with values from memory starting at address I. I is increased by 1 for each value written."

where "I is increased by 1 for each value written." is the important part.

Following this results in the following code:

I wrote a simple Chip-8 emulator in C (mostly taking inspiration from this; to be honest, just rewriting it in C). It uses SDL 2.0, which I definitely have installed.

As I tried compiling the files (gcc main.c chip8.c -o chip8), I got this stack of errors:

i want to run opengl and i also want that my c code is executed... xD After the window is created no code is executed... is this normal ? or do i need just to understand opengl a bit better :D

Maybe i need to put my c code in some opengl loop xD like into the idle function^^

I'm making a project and in order to assist in building, I'm using CMake.

However, I notice that I can't debug.

Here's my launch.json:

I wrote a Chip-8 emmulator in JavaScript (source) and made a playable browser version here.

It contains an HTML select:

I am trying to share as much code as possible between emulators and a CLaSH implementations for CPUs. As part of this, I am writing instruction fetching & decoding as something along the lines of