Hacking the NES With Lisp

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Posted by Unknown on Monday February 6, 2012 @02:00PM from the covert-alien-technology dept.

Andy Hefner has a detailed blog post covering his quest to program an NES with the assistance of Common Lisp. He developed a new 6502 assembler, a mini-language for composing musical sequences, and a neat demo (rom image).

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a strange mix of nausea and admiration by decora · 2012-02-06 14:18 · Score: 5, Funny

on the one hand, this guy has re-implemented assembler with lisp syntax.
on the other hand, this guy has re-implemented assembler with lisp syntax.
1. Re:a strange mix of nausea and admiration by Dwedit · 2012-02-06 14:22 · Score: 4, Informative
  
  Yeah, when you're writing Assembly, it's still assembly. Using lisp to make macros doesn't change the langauge.
2. Re:a strange mix of nausea and admiration by Hentes · 2012-02-06 14:34 · Score: 3, Interesting
  
  Well he wasn't the first one to do it, Common Lisp already has a disassemble command.
3. Re:a strange mix of nausea and admiration by MightyMartian · 2012-02-06 14:35 · Score: 4, Funny
  
  Great. Now I can run Super Mario Bros. in Emacs!
  
  --
  The world's burning. Moped Jesus spotted on I50. Details at 11.
4. Re:a strange mix of nausea and admiration by Anonymous Coward · 2012-02-06 14:44 · Score: 5, Funny
  
  This reminds me of the old quote "Emacs is a wonderful operating system. All it's missing is a decent text editor."
5. Re:a strange mix of nausea and admiration by Anonymous Coward · 2012-02-06 15:07 · Score: 5, Funny
  
  on the one hand, this guy has re-implemented assembler with lisp syntax.
  on the other hand, this guy has re-implemented assembler with lisp syntax.
  and on the gripping hand, it's the world's first assembler that requires you to start lines with seven parentheses and rewrites itself at runtime.
6. Re:a strange mix of nausea and admiration by Darinbob · 2012-02-06 17:07 · Score: 4, Informative
  
  The earliest lisps had assembler. It was sort of normal in a way because assembler was your language of choice for this sort of thing. C didn't exist yet, Fortran was just wrong, the other procedural languages were bulky, etc. Machines were low on memory and you often wanted to machine specific actions, you were writing your own runtime library as you went. So even as far back as Lisp 1.5 documentation discusses how to use assembler.
  The earliest lisps had compilers as well which went well with assembler written functions. Your programming environment was often a stack of cards that were loaded into a machine, or a tape that was read. So stopping to edit/compile/link/load was often impractical compared to just dumping some assembler while still in the interpreter (though of course if you crashed the machine you had to hide until pitchfork wielding mob stopped looking for you).
  The thing people remember most about Lisp other than parentheses are CAR and CDR functions. These are named for specific fields in a PDP 36-bit word which were accessible via machine instructions.
7. Re:a strange mix of nausea and admiration by ratboy666 · 2012-02-06 17:22 · Score: 5, Interesting
  
  Read the fine article. Using CL does substantially change the language. Specifically, note the higher order manipulation of the eventual low-level program that the author achieved using promises (delayed evaluations). Basically, "threading while assembling".
  Also, notice the ease of introducing higher-level flow control constructs (IF and UNTIL) into assembler. And the elimination of a second assembler pass by use of promises for forward references. It's kind of "magic" -- the correct data will be there when it's needed!
  In this use-case, CL is a notational system for NES programming. It probably shouldn't be called "assembler" anymore, as the power of CL can be brought to bear in the process of generating the desired machine code.
  
  --
  Just another "Cubible(sic) Joe" 2 17 3061
8. Re:a strange mix of nausea and admiration by Darinbob · 2012-02-07 07:23 · Score: 2
  
  Close but not exact. I got it wrong too, it wasn't a PDP but an IBM.
  These both were fields from the same register ( bit words and the computer allowed either 15 or 16 bit word addresses). So according to Wikipedia the definitions were:
  "Contents of the Address part of Register number"
  "Contents of the Data part of Register number"
  And a couple other tiny fields that initially were in Lisp but were later dropped.
  Yea, it's kind of weird. The PDPs used at MIT later were 36 bit and also allowed sticking two word addresses into a single word (byte addresses required a full word). So it was very handy for doing CAR/CDR in a single word there.
That's hot by Anonymous Coward · 2012-02-06 14:22 · Score: 3, Interesting

I think that is the coolest thing I have seen in a while. Nothing like the king of all high level languages generating low level machine code.
Re:Nostalgia is a powerful force... by ObsessiveMathsFreak · 2012-02-06 14:38 · Score: 2, Insightful

Are you kidding?! There are probably more working NES consoles out there than N64 or Nokia N-gages.

--
May the Maths Be with you!
Re:Nostalgia is a powerful force... by CohibaVancouver · 2012-02-06 14:50 · Score: 2

Exactly right. I can think of 10 different closets right now that have NESes inside.
Re:Nostalgia is a powerful force... by Anonymous Coward · 2012-02-06 15:10 · Score: 5, Funny

Those NES boxes are quite comfortable with their sexuality, thank you very much, and just value their privacy. If they want to stay in the closet, who are we to disagree?
This is what Slashdot needs more of by comrade+k · 2012-02-06 15:14 · Score: 5, Interesting

Bravo, Slashdot. This is the kind of stuff that the geek crowd finds interesting. Is it useful? Nope. Is it cool and borderline bizarre? Yep!

--
"Every vision is a joke until the first man accomplishes it; once realized, it becomes commonplace." -Robert H. Goddard
1. Re:This is what Slashdot needs more of by wierd_w · 2012-02-06 15:44 · Score: 3, Interesting
  
  What I have always wondered about, is just how far can you push one of these old systems?
  Like the snes.. it was designed to accept a 3rd party cpu inside the cartridge, in addition to the game rom.
  What would happen if you built what would essentially be rom code toolbox routines to access the snes's hardware, and then switch execution to a more powerful/more modern low energy cpu, like an arm?
  You would use the snes as an input device (they did make a snes mouse.....), and as the graphics hardware, but run all the heavy lifting on the arm instead of the 6500 series cpu. Other than the rom routines to do the interface, everything else is handled by a shared ram bank and an sdcard slot put into the cartridge.
  Why? So you can run linux on the snes. Why? Because you could.
  I bet you could do some really clever stuff by simulating a framebuffer.
2. Re:This is what Slashdot needs more of by DigiShaman · 2012-02-06 15:59 · Score: 3, Interesting
  
  Some of the best Z80 ROM music I've heard has to be M.U.S.H.A (Musha Aleste) on the Sega Genesis (Mega-Drive). Herzog Zwei comes in a close 2nd place. The composers were Gods, and they got paid to do what they loved to do. You've got to admire that kind of talent.
  
  --
  Life is not for the lazy.
Re:Nostalgia is a powerful force... by Pseudonym+Authority · 2012-02-06 15:28 · Score: 4, Funny

I truly extend my condolences that your pet project didn't get featured on Slashdot and that it has made you bitter and jealous of the work of others.
Re:Nostalgia is a powerful force... by Osgeld · 2012-02-06 15:43 · Score: 2

wow there killer, way to think outside of the box, you installed software on your pc and let nintendo tell you what you could do! we need more people like you and less of these retards doing interesting things with obsolete machines.
Re:Nostalgia is a powerful force... by EETech1 · 2012-02-06 16:28 · Score: 2

Does that C&C lathe play CNC Music Factory
Or is it a...
Command and conquer lathe controller?
I'm not vicious or malicious, just lovely and delicious. OSLT.
Cheers!
6502 assembler in Logo by leighklotz · 2012-02-06 17:23 · Score: 2

I wrote a 6502 assembler in Logo in 1981 and we shipped it with the utilities disk.
Paul Graham will definitely... by curious.corn · 2012-02-06 18:45 · Score: 2

send him a crate of beer ;)

--
Mi domando chi Ã il mandante di tutte le cazzate che faccio - Altan
Looks like Henry G. Baker's COMFY 6502 compiler by dwheeler · 2012-02-06 20:50 · Score: 3, Interesting

Fun! This 6502-assembler-in-LISP looks similar to Henry G. Baker's "COMFY" 6502 compiler (described in "The COMFY 6502 compiler", SIGPLAN Notices, 1997). You can check out the COMFY-6502 implementation that uses Common Lisp (sadly this appears to be entrapped in the ACM non-commercial-use-only license, though for 6502 code that isn't very limiting). One cool thing about the approach of using LISP as an "assembler" in general is that unlike many traditional macro assemblers, this approach can easily do stuff like choose the optimal instruction set for branches because it can determine if it's in range for a short branch and use them when available. You can do it other ways, of course, but it's pretty elegant in LISP. Those interested in this sort of thing might like my page on 6502 Language Implementation Approaches or my page on making LISP-based languages more readable (especially sweet-expressions).

--
- David A. Wheeler (see my Secure Programming HOWTO)
thats b/c "this stuff" became illegal by decora · 2012-02-06 22:06 · Score: 4, Insightful

if you tried to do what this guy is doing for NES with a Sony Playstation or IPhone you would sued and threatened with millions in legal bills. If you don't believe me, ask George Hotz.
slashdot didn't move away from geeky stuff... certain corporate interests decided to attack the entire principle of DIY at its core. you can't expect slashdot to be silent about that.
Re:Nostalgia is a powerful force... by windcask · 2012-02-07 00:45 · Score: 3, Insightful

Art is about creative self-expression. If someone feels that writing an assembler for a 25 year-old console and making it 'go bloop' expresses himself in ways that modern technology cannot, what's the harm in that? It's neat. He obviously isn't trying to get rich or serve any other practical purpose with this.