Re: [avr-llvm-devel] Current Status?

[Sherard D. <sc...@gm...>]

Thanks for responding Borja. I do have a question, posed to everyone
really. Does anyone know where I can find a reference for which
instructions are available for which AVR architectures? Haven't been
able to stumble upon one in my searches.

Thanks,

On Tue, 2012-01-10 at 17:35 +0100, Borja Ferrer wrote:
> Hello everybody, 
> 
> Sorry about the delay of my reply, but I'm very busy this month with
> my finals. First thing I would like to say is to welcome Sherard. As a
> short summary, the current status to answer Sherard's question is:
> 
> Basically most of what is required to compile sequential code (no
> jumps) is implemented, this includes all memory addressing modes,
> arithmetic instructions, function calls, passing arguments, etc. Last
> thing I finished working on before Christmas was frames and stack
> manipulation. So we can now allocate automatic variables on the stack,
> pass arguments using the stack, and spill registers.
> Next thing I'm going to work on are jumps and conditional code, I'll
> head into this in February when I'm done with my finals, I only had
> time to implement the jmp instruction which was pretty fast to do, but
> conditional code requires a lot more of work.
> 
> Please don't look or work on any code in SVN because that is going to
> be removed, and I doubt it even compiles with the latest LLVM release.
> It's my fault because i haven't uploaded yet any of the work I've done
> out of trunk to SVN but i want to have something in shape before
> commiting it, I think I will do it once conditional code is done.
> Looking in SVN is misleading because it looks as the project is dead,
> but that is totally wrong because we're getting a lot done out of
> there.
> 
> About patches, I would say most of them are updated, I commited a
> patch some weeks ago for the register allocator, but if you want to
> check them it's ok. Related to code, i think patches are the only
> useful thing SVN has now, the backend code will go away.
> 
> Since the LLVM backend code is not yet commited, I would suggest as
> John said working on regression tests, we're going to need this soon,
> and we're getting behind on this because we need a good test suite to
> catch as many errors as possible, so patches there are welcome.
> Something similar to what the MSP430 backend has would be a decent
> start. Tests related to arithmetic ops, function calls, testing ABI,
> and other things you can think of that dont require jumps. 
> Also on the other side, a lot of work is needed in Clang, we need to
> support many of the custom extensions AVR has like address spaces or
> interrupt handlers, so work is needed there aswell. We discussed some
> months ago about how to deal with address spaces but we didnt reach to
> any formal decisions, so if you want to work on that aswell you're
> welcome. In fact, if you want to work both with tests and this that
> would be great :)
> 
> Another thing, I've noticed that the new register allocator in 3.0
> uses less stack memory than IAR or GCC so that is something positive.
> I see a lot of potential in getting better code than gcc in the
> future, because with the current generated code which is not optimized
> at all (i want to leave that for a later stage) we're getting in par
> or improving what gcc does and sometimes getting a bit longer code but
> nothing that is too bad to worry. But once we introduce custom patters
> for instruction selection things will improve exponentially.
> 
> If you want to ask any specific questions after this general summary?
> ------------------------------------------------------------------------------
> Write once. Port to many.
> Get the SDK and tools to simplify cross-platform app development. Create 
> new or port existing apps to sell to consumers worldwide. Explore the 
> Intel AppUpSM program developer opportunity. appdeveloper.intel.com/join
> http://p.sf.net/sfu/intel-appdev
> _______________________________________________ avr-llvm-devel mailing list avr...@li... https://lists.sourceforge.net/lists/listinfo/avr-llvm-devel