danirod / chip8 Goto Github PK

This is a marker issue that has been created for post-referencing. It's already a Known Issue and it's getting fixed.

It's found that when the emulator shuts down on Linux and MacOS X, it crashes dumping to the terminal the following error message:

chip8(2920,0x7fff7a09b310) malloc: *** error for object 0x7f9c9d81d200: pointer being freed was not allocated
*** set a breakpoint in malloc_error_break to debug

This behaviour cannot be reproduced on Windows platform. On MacOS X host it even freezes sometimes for a few seconds keyboard and mouse.

Segun esta pagina [http://mattmik.com/chip8.html] lo correcto seria:

8XY6 - Store the value of register VY shifted right one bit in register VX
Set register VF to the least significant bit prior to the shift.

8XYE - Store the value of register VY shifted left one bit in register VX
Set register VF to the most significant bit prior to the shift.

Since CHIP-8 is just a specification and it's up to the actual machines to set the clock speed, it would be nice if the user could set the clock speed for the game. This could change the frame speed as well since on recent releases the emulator seems to be faster in terms of emulation speed.

CHIP-8 eats way too much CPU on the host machine.

Run the emulator on any operating system and check the CPU usage. It will go up to 90%-100% and stay until emulator gets closed. This is a problem on less powerful computers and it can drain batteries on laptops.

This is a reminder issue so that I don't forget about this next time I work on this emulator.

init_context(struct context_t*) is called on main function but no actual check for the return value of that function is being made. Source code. This means that if the context cannot be initialized properly and an error happens, the program won't notice until it tries to do something 'illegal' and crashes. This should be fixed, actually.

This is what happens when you try to release overnight: you fail. Go to sleep, release next morning. I've learnt this lesson the hard way.

No stdout, no stderr, no error message printed if just .\chip8.exe is executed.

No stdout/stderr is because of -mwindows, which is a flag required to treat the application as a graphical (Win32) application instead of a console application. The deal is that unless the application is graphic, Windows will suck stdout/stderr and not print it to cmd.exe (MSYS shell works fine here).

No errors mean no feedback. If the user just double clicks chip8.exe icon he won't notice what is going on because there is no way for telling the user what he is supposed to do (drag a ROM icon to the application?, provide an argument via terminal?).

This is a marker issue. It's already a known issue and it's being fixed but is here for referencing purposes.

During game execution display flashes a lot on each frame. It seems that only pixels that have changed value flash. That may explain why on PONG everything just blinks out like crazy but on INVADERS start screen, only letters inside the board blink.

This is a marker issue.

I'm going to split this project into two separate parts:

• Library: is going to be named libchipocho. Core of the emulation will be here.
• Main client: is the SDL client that uses libchipocho to run an actual emulator.

Some other things to do during this refactor are:

• Split project into headers and source files.
• Add some unit tests.
• Proper documentation system.

Yes, these changes are inspired by what I'm doing right now at my other emulator project.

Pull requests may be blocked while this task is going on since I'm moving a lot of files. I don't know how much time will this task take.

This thread talks about MEGACHIP-8 support. It has a lot of features such as up to 32 MB of RAM, digital sound, bigger screen, indexed colors, and still CHIP-8 compatibility plus SCHIP compatibility. Demos look great and it might be awesome for creating advanced content.

• Tools: http://www.chip8.com/?page=92 (the MEGACHIP DEVKIT contains the spec, still haven't read it).
• Source: https://twitter.com/hugomartin89/status/726954487529766913