Re: ADA CORE TECHNOLOGIES ANNOUNCES GNAT-TO-JAVA SYSTEM

[Stephen Leake <Stephen.Leake@gsfc.nasa.gov>]

Robert Dewar wrote:
> 
> Stephe says
> 
> <<This sounds like you are NOT planning on adapting the backend of gcc to
> write JVM byte codes, but are instead implementing a new backend in Ada.
> This is cool! Will this backend be as data-driven as gcc? What I really
> want to know is; will I be able to adapt the new backend to my flight
> processor, and abandon gcc? gcc is great, but adapting it means writing
> K&R level C; I'd much rather be writing Ada95!>>
> 
> That's right -- making GCC produce JVM byte code makes no sense, since the
> level of abstraction is quite wrong. What we are doing is a completely new
> backend that generates JVM from the GNAT tree.

I guess I need to read up on the JVM. I've been assuming it was at the
same level as the UCSD Pascal P-machine; basically a virtual 32 bit
processor, with operations like a current-generation RISC chip. I guess
this is wrong.

Can anyone recommend a _good_ intro to the JVM? I go to Borders, and
have a hard time choosing from all the books promising to teach me Java
in 10 days :).

> 
> As to your question about adaptation, if you believe that going through
> JVM and JIT compilers etc can yieled acceptably efficient code then indeed
> you can follow this path (and perhaps you can also get a job as a publicity
> agent for Sun :-)

Yeah, and I can deliver a Working System Real Soon Now. I hoped I would
be able to take your new backend, and make it generate assembler for my
chip, instead of "assembler" for the JVM.

Even if you are not replacing gcc for real processors now, maybe you
could try to make it possible to eventually use this backend as a
replacement for part of gcc (talk about vague requirements!). We need to
get away from K&R in the core of our compilers sometime! 

I guess this is what Intermetrics has; the AdaMagic front end
accommodates several backends. Is that all written in Ada?

-- 
- Stephe