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Writing My Own Nes Emulator


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#1 yaazz

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Posted 06 December 2009 - 12:49 AM

I was bored one day and decided I wanted to write my own NES emulator.
So I started looking for information on the NES. I found out it uses a modified 6502 processor, that has added function for sound. Found some info on the PPU and started hacking away.


The CPU Emulation is basically done, and works fine, lately I have been working at getting video up and running..
Ive been busy with finals in the last little while so its not finished, but I figured I would put up some screens anyways.

NES outputs data in 8*8 pixel tiles, so the first thing I did was make sure I was outputting the correct tiles.
I did this by having the emulator "run" in the terminal.... kinda amusing, im definitley going to leave support for this in the final version
If you use your imagination you can see the title screen in the terminal window. Super mario bros does
this weird thing where it stores the machine code to display the "SMB" logo and the copyright underneath
it in the section of cartridge rom that stores the background images. for some reason this doesn't work yet
ill figure it out at some point...
Sorry for the huge images

IPB Image

Then I went from that, to having simple OPENGL output. NES has 64 possible colors, but I only supported 4 in this demo to see if it was handling scanlines right.
IPB Image

This version is the latest (from about a week ago). It supports all colors now, but due to a bug in how I am
handling the attribute table of the background it is only using 4! Still neat to have output though
IPB Image


More updates as I keep working on this coming up this week sometime


#2 CattyKid

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Posted 25 December 2009 - 05:42 AM

really cool, looks like it is coming along pretty well.
i really like that text output mode. looks really neat, actually.

#3 liquidbings

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Posted 09 March 2010 - 04:48 PM

Liking the work/progress biggrin.gif any updates since this? Hope all is moving smoothly with your work smile.gif

Thanks again!

#4 yaazz

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Posted 09 April 2010 - 11:36 PM

Thanks? Your welcome I guess!

Progress has been extremely slow as of late. School/JTAG has taken almost all of my time, but as soon as the summer break comes im going to release this. Also, be prepared for a REALLY cool feature that I have kind of working..... This hasn't been done before, and its really cool.

#5 RESMONKEY

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Posted 13 May 2010 - 05:24 PM

Neato. A NES emulator is one of my summer projects I will be starting soon. Did you get your info from NESdoc PDF file?

#6 yaazz

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Posted 26 May 2010 - 10:18 PM

Initially I did read the NESDoc, but when I started writing code, I quickly found out it's not much more then a reference/interesting read. Go to http://nesdev.parodius.com/#Docs if you want info that will actually assist you.

Feel free to PM me or post a message in this topic if you think I can help you.

#7 kennethk

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Posted 28 May 2010 - 05:42 PM

Will this be available for windows users also? Just asking because I noticed you work with MACs. tongue.gif




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