What's new

Problems with my CHIP8 emulator

Sylan

New member
I've started working on my first emulator, based around the CHIP8 system. I've finished all of the opcodes, and gotten it so that when ran, the first frame of the ROM will show up successfully. However, in my first attempts after completion, the emulator would not do anything else past that. I assumed it was a problem of input not being recognized, so I changed the input system to be based on the one used by an open source CHIP8 emulator I was learning from, and now the emulator simply locks up after the first frame. Can someone give me some insight as to what the problem is? Thanks.

Source pulled: See update.
 
Last edited:
OP
S

Sylan

New member
UPDATE:
I found the problem, after messing it with it for a few hours. Turned out to be really simple. That said, my first emulator is now completed. Sorry for bothering here.
 
OP
S

Sylan

New member
Thanks, but now that the code is finished, some new problems are coming up. Most ROMs I have will draw the first frame to the screen, then stop doing anything (the program does not crash as before, but the games stop running). The only one that works with any response is CONNECT4(included in the David Winters CHIP8 download), and it randomly places markers on key presses, with some tearing graphics. I've checked just about every possible issue I could think of now. I'd appreciate it if there's anyone who thinks they may be able to look over it.
 
OP
S

Sylan

New member
New note:
A friend who's been helping me work on this project made a basic disassembler for CHIP8 ROMs. In a few of them, we found opcodes that didn't exist in any documents on the CHIP8, and were not interpreted for that reason. Any reason these might be showing up so frequently?
 
OP
S

Sylan

New member
And another:
My friend noticed a problem with their disassembler; the opcode check didn't include breaks in the switch under the opcodes that included multiple under one starting letter (such as Fx55 and fx65). After adding the breaks to theses cases in both his disassembler and my interpreter, CONNECT4 graphics stopped tearing, and SPACE INVADERS ran successfully. Still having some issues with other ROMs, but the first fully playable game is a huge success.

UPDATE: PONG2 also working.
 
Last edited:

Cyberman

Moderator
Moderator
1: congratulations it's always great when something works (really it feels great)
2: perseverance pays off so keep moving forward.
3: there is a chip 8 thread in here (although i don't mind occasional leakage into the regular programming area because it's been a bit slow).

Cyb
 

Top