6 ms·

JSNES: A Javascript NES emulator

132 points by jawngee 17y ago

timdorr 17y ago
I thought the Javascript CAPTCHA solver was insane. This takes the cake. Next step, do like Cappuccino and "compile" the NES rom's back to native Javascript. At that point, I think my head might explode.
- wallflower 17y ago
  > Next step, do like Cappuccino Agreed. Google Web Toolkit was a step in this direction. Once you can develop in a language of your choice (Java, Python, Ruby, etc.) and have the user interface code auto-magically compiled into equivalent functional HTML5 and JavaScript so that it can run on any browser, I think Flash will begin its fall and decline. However, I think Adobe probably has some skunkworks project to target ActionScript/Flash as pure HTML5+Javascript output (they'll sell the graphical development tool and give up on browser domination). Adobe is working towads the holy grail of UI design tools. To build the tool that lets wireframes become functional. They are working on FXG. I imagine, internally, that there are major turf wars on continuing with Flash native vs HTML5. http://opensource.adobe.com/wiki/display/flexsdk/FXG+1.0+Specification http://opensource.adobe.com/wiki/display/flexsdk/FXG+1.0+Spe...
  - thomasfl 17y ago
    Interesting. With Html5+Javascript (H5J) and fast JavaScript engines like Chrome there will be few technical reasons left for using flash (and flex).
- zackattack 17y ago
  What javascript captcha solver?!
  - pjonesdotca 17y ago
    here you go -> http://userscripts.org/scripts/review/38736 http://userscripts.org/scripts/review/38736
  - pjonesdotca 17y ago
    also -> http://ejohn.org/blog/ocr-and-neural-nets-in-javascript/ http://ejohn.org/blog/ocr-and-neural-nets-in-javascript/
chaosmachine 17y ago
I wonder how far behind a n64 emulator is. Does anyone else remember when UltraHLE showed up in early 1999? Nobody expected the Nintendo64 would be emulated that soon (GameCube was still 2 years away at that point).
WALoeIII 17y ago
This is so cool. Props.
nopassrecover 17y ago
Awesome, but if I get deselected I can't get it to pick up keys again. In firefox couldn't even get it to pick up keys to start with.
iman 17y ago
Very impressive, but performance sucks, even in google chrome. Keep in mind that the 486 is capable of fully emulating the NES. The truth is that javascript will simply never be appropriate for tasks such as this. It is too slow and no amount of magic fairy dust optimizations will make it come close to high performance languages. Java on the other hand (as much as I hate java) can do high performance stuff. Here is a java applet NES emulator, with sound: http://www.nescafeweb.com http://www.nescafeweb.com
- idm 17y ago
  WOW - I just installed Chrome for Intel OSX, and this is amazing. The performance in Firefox 3.5 was unplayable, while Safari 4 was much better, but Chrome is insane. I can't believe what I just witnessed: a playable javascript NES emulator. I think this is a pretty significant step for the "web," actually. See here for more info about Mac Chrome: http://dev.chromium.org/getting-involved/dev-channel http://dev.chromium.org/getting-involved/dev-channel
- mhansen 17y ago
  I heard an interview with Brendan Eich from last year where he says there are still many javascript optimizations that haven't been attacked yet, that there is still a lot of low-hanging fruit. He also predicted speeds bordering on C within a few years. [EDIT] Source: http://perseus.franklins.net/hanselminutes_0130.pdf http://perseus.franklins.net/hanselminutes_0130.pdf
  - wallflower 17y ago
    Yes, Java is a statically-typed language but remember how Java performed before JIT compilers? It was closer to Perl than C.
- thomasfl 17y ago
  Even if JavaScript is slow as a turtle, Html5+JavaScript (H5J) is still a lot better for making simple animations than applets. With WebKits 3D effects, animation will look just as slick and smooth as flash.
- 17y ago
rms 17y ago
Did Nintendo officially give up on litigating for NES ROMs? I'm wondering how something like this stays on the internet while supplying ROMs.
- arketyp 17y ago
  I've heard (can't find a source) that Shigeru Miyamoto (creator of most Nintendo's hit titles) personally has a lighthearted stance to the whole emulator/ROM scene and basically thinks it is nice that people still play the games.
  - rms 17y ago
    Sounds very plausible. It just seems odd that Nintendo would allow this to go on while still making all of these games available for purchase via the Wii store.
    - nuclear_eclipse 17y ago
      I don't think the Wii's target market really crosses much with the people who would really use ROMs on a PC as a substitute for the real thing...
    - jiaaro 17y ago
      not really... the game play experience on a tv is very different from a few hundred pixel wide square in a browser
maxklein 17y ago
Ah, Javascript in browsers. Making things PCs did in 1999 seem wondrous once more.
- DrJokepu 17y ago
  I'm looking forward the day someone comes up with the brilliant idea of writing an OS in JavaScript.
  - chaosmachine 17y ago
    http://en.wikipedia.org/wiki/YouOS http://en.wikipedia.org/wiki/YouOS
  - btilly 17y ago
    That was done years ago: http://www.masswerk.at/jsuix/ http://www.masswerk.at/jsuix/. Click on "terminal" at the top.
    - jacquesm 17y ago
      impressive! JavaScript is one of the few languages where you keep being surprised with what can be done with it. For the longest time I saw it as pretty limited, then one day somone shows me an apple II emulator in javascript.
daeken 17y ago
Very neat, but it's a shame that interpretation is used. With the speed of current Javascript implementations, dynamic recompilation (block-based recompilation to JS functions, specifically) is insanely fast. A while back, http://6502asm.com/ http://6502asm.com/ popped up with a web-based 6502 (chip used in the NES, Apple ][, and many others) emulator. I stumbled upon it and in a matter of hours, I patched it to become the first (to my knowledge) dynarec emulator in JS. You can see a live version here: http://ironbabel.googlepages.com/6502.html http://ironbabel.googlepages.com/6502.html This same technology could easily be applied to JSNES for considerable speedups.
- jacquesm 17y ago
  Re http://ironbabel.googlepages.com/6502.html http://ironbabel.googlepages.com/6502.html Assemblers don't compile, they assemble. Neat hack though!
  - jcl 17y ago
    Yes, but it's also correct to say that he wrote a compiler. He is taking the assembly code you type in and translating it to machine code, then he's translating the machine code to JavaScript source, then executing that source directly. Translating a program from one language to another is compilation, by definition. While the first translation step could also be considered assembling, the second cannot.
- yan 17y ago
  Do you have more resources on optimizations when targeting js?
  - daeken 17y ago
    No, sorry. I haven't done much in the way of optimizations with JS, but I'll explain how this is optimized. This is actually a simplified version of the structure used in IronBabel (emulator platform of mine, http://sourceforge.net/projects/ironbabel/ http://sourceforge.net/projects/ironbabel/ ) You have a hash table mapping an address to a block length, block function, and a hash/checksum. Your execution loop looks for the program counter in the hash table. If it exists, you take <block length> bytes from the program counter, hash/checksum it, and compare it against the hash table entry. If the cache entry misses, you need to recompile the block. Starting from the program counter, read instructions and rather than executing the operation (as in an interpreter), you append the operation's code to a string. When you hit a branch and output the code, you break the loop. You now have the code of the block. Wrap it in a function, eval it, and put the function in the cache. There are a number of optimizations that can be done (see IronBabel for specifics), but the easiest is to group blocks into a state machine. Simply push all of the code into a big while(true) { switch(PC) { case 0xDEADBEEF: ... }} and break out if you hit a block that isn't in the state machine.
_ck_ 17y ago
I sure hope flashblock comes up with an optional canvas block because it all starts with fun and games until advertisers realize "ooh hey we can skip flash and write the content anywhere without filtering" and then you've got "hit the monkey" all over again.
- jcl 17y ago
  I wouldn't be too concerned... The number of people using Flashblock is vanishingly small, and their eyeballs are worth less for many products. Also, Flash cookies are more advertiser-friendly than browser cookies.
Pistos2 17y ago
Pretty much unplayable in Opera (10). Opera's key mappings override the game's mappings, and CPU usage is way up there.
audionerd 17y ago
I wonder if sound could be added via the HTML5 <audio> support? You can actually use the data uri scheme for <audio> src. So if you generate WAV data on the fly via JavaScript, and encode it as Base64, you can play it immediately. Here's an example of on-the-fly WAV generation w/ <embed>, but I just tried it in Firefox with <audio> and that works as well: http://sk89q.therisenrealm.com/2008/11/dynamically-generating-a-wav-in-javascript/ http://sk89q.therisenrealm.com/2008/11/dynamically-generatin...

132 points by jawngee 17y ago

I thought the Javascript CAPTCHA solver was insane. This takes the cake. Next step, do like Cappuccino and "compile" the NES rom's back to native Javascript. At that point, I think my head might explode.

wallflower 17y ago
> Next step, do like Cappuccino Agreed. Google Web Toolkit was a step in this direction. Once you can develop in a language of your choice (Java, Python, Ruby, etc.) and have the user interface code auto-magically compiled into equivalent functional HTML5 and JavaScript so that it can run on any browser, I think Flash will begin its fall and decline. However, I think Adobe probably has some skunkworks project to target ActionScript/Flash as pure HTML5+Javascript output (they'll sell the graphical development tool and give up on browser domination). Adobe is working towads the holy grail of UI design tools. To build the tool that lets wireframes become functional. They are working on FXG. I imagine, internally, that there are major turf wars on continuing with Flash native vs HTML5. http://opensource.adobe.com/wiki/display/flexsdk/FXG+1.0+Specification http://opensource.adobe.com/wiki/display/flexsdk/FXG+1.0+Spe...
- thomasfl 17y ago
  Interesting. With Html5+Javascript (H5J) and fast JavaScript engines like Chrome there will be few technical reasons left for using flash (and flex).
zackattack 17y ago
What javascript captcha solver?!
- pjonesdotca 17y ago
  here you go -> http://userscripts.org/scripts/review/38736 http://userscripts.org/scripts/review/38736
- pjonesdotca 17y ago
  also -> http://ejohn.org/blog/ocr-and-neural-nets-in-javascript/ http://ejohn.org/blog/ocr-and-neural-nets-in-javascript/

chaosmachine 17y ago

I wonder how far behind a n64 emulator is. Does anyone else remember when UltraHLE showed up in early 1999? Nobody expected the Nintendo64 would be emulated that soon (GameCube was still 2 years away at that point).

WALoeIII 17y ago

This is so cool. Props.

nopassrecover 17y ago

Awesome, but if I get deselected I can't get it to pick up keys again. In firefox couldn't even get it to pick up keys to start with.

iman 17y ago

Very impressive, but performance sucks, even in google chrome. Keep in mind that the 486 is capable of fully emulating the NES. The truth is that javascript will simply never be appropriate for tasks such as this. It is too slow and no amount of magic fairy dust optimizations will make it come close to high performance languages. Java on the other hand (as much as I hate java) can do high performance stuff. Here is a java applet NES emulator, with sound: http://www.nescafeweb.com http://www.nescafeweb.com

idm 17y ago
WOW - I just installed Chrome for Intel OSX, and this is amazing. The performance in Firefox 3.5 was unplayable, while Safari 4 was much better, but Chrome is insane. I can't believe what I just witnessed: a playable javascript NES emulator. I think this is a pretty significant step for the "web," actually. See here for more info about Mac Chrome: http://dev.chromium.org/getting-involved/dev-channel http://dev.chromium.org/getting-involved/dev-channel
mhansen 17y ago
I heard an interview with Brendan Eich from last year where he says there are still many javascript optimizations that haven't been attacked yet, that there is still a lot of low-hanging fruit. He also predicted speeds bordering on C within a few years. [EDIT] Source: http://perseus.franklins.net/hanselminutes_0130.pdf http://perseus.franklins.net/hanselminutes_0130.pdf
- wallflower 17y ago
  Yes, Java is a statically-typed language but remember how Java performed before JIT compilers? It was closer to Perl than C.
thomasfl 17y ago
Even if JavaScript is slow as a turtle, Html5+JavaScript (H5J) is still a lot better for making simple animations than applets. With WebKits 3D effects, animation will look just as slick and smooth as flash.
17y ago

rms 17y ago

Did Nintendo officially give up on litigating for NES ROMs? I'm wondering how something like this stays on the internet while supplying ROMs.

arketyp 17y ago
I've heard (can't find a source) that Shigeru Miyamoto (creator of most Nintendo's hit titles) personally has a lighthearted stance to the whole emulator/ROM scene and basically thinks it is nice that people still play the games.
- rms 17y ago
  Sounds very plausible. It just seems odd that Nintendo would allow this to go on while still making all of these games available for purchase via the Wii store.
  - nuclear_eclipse 17y ago
    I don't think the Wii's target market really crosses much with the people who would really use ROMs on a PC as a substitute for the real thing...
  - jiaaro 17y ago
    not really... the game play experience on a tv is very different from a few hundred pixel wide square in a browser

maxklein 17y ago

Ah, Javascript in browsers. Making things PCs did in 1999 seem wondrous once more.

DrJokepu 17y ago
I'm looking forward the day someone comes up with the brilliant idea of writing an OS in JavaScript.
- chaosmachine 17y ago
  http://en.wikipedia.org/wiki/YouOS http://en.wikipedia.org/wiki/YouOS
- btilly 17y ago
  That was done years ago: http://www.masswerk.at/jsuix/ http://www.masswerk.at/jsuix/. Click on "terminal" at the top.
  - jacquesm 17y ago
    impressive! JavaScript is one of the few languages where you keep being surprised with what can be done with it. For the longest time I saw it as pretty limited, then one day somone shows me an apple II emulator in javascript.

daeken 17y ago

Very neat, but it's a shame that interpretation is used. With the speed of current Javascript implementations, dynamic recompilation (block-based recompilation to JS functions, specifically) is insanely fast. A while back, http://6502asm.com/ http://6502asm.com/ popped up with a web-based 6502 (chip used in the NES, Apple ][, and many others) emulator. I stumbled upon it and in a matter of hours, I patched it to become the first (to my knowledge) dynarec emulator in JS. You can see a live version here: http://ironbabel.googlepages.com/6502.html http://ironbabel.googlepages.com/6502.html This same technology could easily be applied to JSNES for considerable speedups.

jacquesm 17y ago
Re http://ironbabel.googlepages.com/6502.html http://ironbabel.googlepages.com/6502.html Assemblers don't compile, they assemble. Neat hack though!
- jcl 17y ago
  Yes, but it's also correct to say that he wrote a compiler. He is taking the assembly code you type in and translating it to machine code, then he's translating the machine code to JavaScript source, then executing that source directly. Translating a program from one language to another is compilation, by definition. While the first translation step could also be considered assembling, the second cannot.
yan 17y ago
Do you have more resources on optimizations when targeting js?
- daeken 17y ago
  No, sorry. I haven't done much in the way of optimizations with JS, but I'll explain how this is optimized. This is actually a simplified version of the structure used in IronBabel (emulator platform of mine, http://sourceforge.net/projects/ironbabel/ http://sourceforge.net/projects/ironbabel/ ) You have a hash table mapping an address to a block length, block function, and a hash/checksum. Your execution loop looks for the program counter in the hash table. If it exists, you take <block length> bytes from the program counter, hash/checksum it, and compare it against the hash table entry. If the cache entry misses, you need to recompile the block. Starting from the program counter, read instructions and rather than executing the operation (as in an interpreter), you append the operation's code to a string. When you hit a branch and output the code, you break the loop. You now have the code of the block. Wrap it in a function, eval it, and put the function in the cache. There are a number of optimizations that can be done (see IronBabel for specifics), but the easiest is to group blocks into a state machine. Simply push all of the code into a big while(true) { switch(PC) { case 0xDEADBEEF: ... }} and break out if you hit a block that isn't in the state machine.

_ck_ 17y ago

I sure hope flashblock comes up with an optional canvas block because it all starts with fun and games until advertisers realize "ooh hey we can skip flash and write the content anywhere without filtering" and then you've got "hit the monkey" all over again.

jcl 17y ago
I wouldn't be too concerned... The number of people using Flashblock is vanishingly small, and their eyeballs are worth less for many products. Also, Flash cookies are more advertiser-friendly than browser cookies.

Pistos2 17y ago

Pretty much unplayable in Opera (10). Opera's key mappings override the game's mappings, and CPU usage is way up there.

audionerd 17y ago

I wonder if sound could be added via the HTML5 <audio> support? You can actually use the data uri scheme for <audio> src. So if you generate WAV data on the fly via JavaScript, and encode it as Base64, you can play it immediately. Here's an example of on-the-fly WAV generation w/ <embed>, but I just tried it in Firefox with <audio> and that works as well: http://sk89q.therisenrealm.com/2008/11/dynamically-generating-a-wav-in-javascript/ http://sk89q.therisenrealm.com/2008/11/dynamically-generatin...