Embedded Preverifier Progress
Craig Setera — September 12, 2005 @ 7:57 pm — Status Updates
Since the first days of EclipseME, I have strived to provide a robust development environment for Eclipse users to work with various J2ME toolkits out on the market. Unfortunately, interacting with the various toolkits has proven to be a challenge and a source of frustration for everyone, each with its own set of oddities to deal with. Over the last few (many?) months, I’ve been working on a new preverifier implementation in Java. The idea was to create an implementation that would be easier to attach to from EclipseME, provide better performance and to offer better diagnostics.
I’m happy to say that I’m finally making some progress. This screenshot shows some of the improved diagnostics available from the new preverifier.
There is still quite a bit of work until this feature is fully ready and of the necessary quality. My hope is that I will be able to get an in-progress version into an upcoming release. Initially this support will be turned off by default with a preference for controlling which preverifier to use. We will need everyone’s help to test the new function with the hope of eventually enabling the new preverifier full time.
September 13th, 2005 at 11:39 am
How do you plan to handle the differences between the preverifiers? I know that LG uses a different preverifier that does not produce the same output as the regular one. Do you know where the differences show up?
September 13th, 2005 at 12:04 pm
This is a very good question. I was under the (mistaken?) impression that all of the preverifiers had to follow the J2ME specifications and would therefore output the same bytecodes. Do you have any more information on the differences or pointers to where I could find more information? At worst, we would keep the older ability to call out to external preverifiers.
September 15th, 2005 at 12:46 am
We had independently developed a preverifier in conjunction with our mBooster J2ME optimizing compiler. Our experience indicated that the J2SE JVM specification + J2ME specifications are far from watertight when it comes to pre-verification - in fact it is probably the most loosely defined aspect. Some phones (I won’t name names here) are also non-compliant to the specifications around the corner cases - obviously these are never specified.
The best starting point is CLDC 1.1 specification Appendix A. However please bear in mind that the specification represents the ideal and not necessarily what is implemented by Sun’s preverifier or the JVMs in use.
Please feel free to drop me an email.
September 15th, 2005 at 3:41 am
What about the differences between CLDC 1.0 and CLDC 1.1? CLDC 1.1 does support floating point arithmetics and I remember having some trouble with Antenna on this, as parts of M3D (JSR-184) do use floating point arithmetics…
September 15th, 2005 at 7:07 am
David,
The preverifier does support CLDC 1.1. The screenshot obviously shows the preverifier in use for CLDC 1.0, but it will be able to handle CLDC 1.1 as well.
September 26th, 2005 at 4:32 pm
Comment spam is picking up on this entry. I’m going to close comments on this item at this time.
September 30th, 2005 at 2:22 pm
[...] The next release is next. With any luck, we will be releasing a new EclipseME release within the next few weeks containing more Motorola toolkit support and the new built-in preverifier. In the medium term, we have a set of plans beginning to form to rework the internals of EclipseME to make it easier to add new toolkits to EclipseME and share them with all users. Checking the bug list and enhancement requests, makes it clear that there is no shortage of work to do on EclipseME. [...]
October 17th, 2005 at 7:49 pm
[...] A new version of EclipseME has been released. In this version, you will find lots of bug fixes and a few new features. Kevin spent quite a bit of time fixing up the Motorola toolkit support in this release. Unfortunately, the Motorola toolkits have a few problems, but at this point EclipseME is doing as much as is possible for these toolkits. This version also offers the first release of the new built-in preverifier support. Although this support should be considered alpha quality at this point, with the help of EclipseME users this support will mature quickly. [...]