Re: [9fans] speaking of kenc

[Paul Lalonde <plalonde@telus.net>]

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On May 4, 2007, at 2:24 AM, C H Forsyth wrote:
> if it's on (say) a DSP, it's a bit of a mixture of that and people  
> thinking that
> language design stopped with C, so the language provides too little  
> scope for a compiler sensibly to do the work.

This is the one that worries me most.  Looking at the SPUs on Cell,  
kencc won't let me make decent code for them: the vast space of  
vector instructions requires extensive language extensions to use  
well.  The overhead of a function call defeats the careful  
interleaving of those instructions.  The Cell architecture  
specification includes considerable language extensions to handle  
this, but it's all implemented in a big GCC module.  Ick.

I write a lot of SPU code in my day job, and although C++'s class  
mechanisms are useless, the vector extensions are incredibly useful,  
and when combined with the C++ template mechanism (Yikes!) generates  
very good code.  What this tells me is that C and C++ aren't good  
languages for SPU coding, and I should be thinking of something more  
clever that will make our tasks easier, but getting code done has  
trumped language work.

This will be increasingly on my mind as my cell port comes online and  
I come to wanting my SPUs to work.

> stunning (in every sense).   i pick on that one because the DCRs  
> were ADDED relatively late
> in the powerpc history.  perhaps it was just a form of mid-life  
> crisis.

FWIW, the DCRs are gone from Cell.

Paul

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