Squawk

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Squawk

Postby temp12 » Fri Feb 15, 2008 2:07 pm

Sun has released the squawk JVM of SunSPOT as a open source under GPL: https://squawk.dev.java.net/. Maybe we could use its code for the improvement of lejos.
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Postby gloomyandy » Sun Feb 17, 2008 3:46 pm

Interesting. There are many parallels with the way that leJOS has been implemented (including things like pre-linking the byte code, using a simplified interpreter with more static byte code to allow execution from flash etc.). For me the most interesting part of squawk is the debug interface, perhaps we could make use of that....

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Postby bbagnall » Mon Feb 18, 2008 3:09 am

I didn't find much in subversion in the way of Java source files, so either the API is very limited or I wasn't looking in the right place. Did anyone find where the main Java packages reside?

There was a Sun employee named Simon Ritter who was a big user of leJOS RCX. The last thing I heard from him in 2006 was that he was going to work on SunSpot and I think Squawk. I wonder if he did anything on this project.
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Postby gloomyandy » Mon Feb 18, 2008 1:46 pm

Hi Brian,
There are hundreds of Java files in the svn trunk (most of the VM is Java as are all of the tools etc.). Which bit of source are you looking for?

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Postby bbagnall » Wed Feb 27, 2008 6:57 am

Which subdirectory do you find the standard Java library such as java.lang?
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Postby gloomyandy » Wed Feb 27, 2008 7:21 am

Hi Brian,
Take a look at...
https://squawk.dev.java.net/source/brow ... /cldc/src/
and below...

Squawk implements the Connected Limited Device Configuration variant of J2ME, hence the java files tend to hide under the cldc name...

All the best

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Postby bbagnall » Wed Feb 27, 2008 3:21 pm

That's where I was looking before but I guess they just have a very limited API. There are not many packages, and those packages that appear (like javax.microedition.io and java.util) are practically bare.
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Postby gloomyandy » Wed Feb 27, 2008 3:55 pm

Hi Brian,
There are a lot more classes under the device/squawk specific parts of the class libs...
Take a look at
http://www.sunspotworld.com/docs/Purple/javadoc/
To see the full API doc for the sunspot version....

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Postby temp12 » Thu Mar 06, 2008 2:29 pm

bbagnall wrote:That's where I was looking before but I guess they just have a very limited API. There are not many packages, and those packages that appear (like javax.microedition.io and java.util) are practically bare.


squawk supports IMP 1.0 which is practically MIDP without GUI.
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Postby temp12 » Thu Mar 13, 2008 5:21 pm

there is already a project which is trying to port squawk to nxt. See: https://nxtsquawk.dev.java.net/
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Postby gloomyandy » Thu Mar 13, 2008 11:17 pm

It will be interesting to see how they get on... The nxt has way less memory than a Sun Spot (64k Ram v 256k 256K flash v 2Mb) so I suspect that they may have to make some changes to the memory layout (and probably the garbage collector). The Sun Spot is also based on an ARM9 core v the nxt ARM7 this makes it about 5 time faster. Will be interesting to see if they can continue to handle some of the devices from Java...

The two projects are actually very similar in terms of overall structure... Same compile and pre-link model.

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