[Openmcl-devel] Using vecLib framework from OpenMCL?

Phil pbpublist at comcast.net
Tue Aug 29 02:10:41 PDT 2006

On Aug 29, 2006, at 3:21 AM, Gary Byers wrote:

Thanks for the excellent discussion on the various considerations re:  
SIMD.  The memory alignment discussion will help me with what I'm  
thinking about trying (SIMD via FFI)...

> I was never able to come up with an even vaguely lisp-like way of
> integrating SIMD stuff with a 32-bit lisp; whenever the issue arose,
> I generally suggested that it'd be better to wait for 64-bit ports
> because of the alignment issues.  I'm not sure what the priority on
> this should be,  but I do recognize that I no longer have that excuse.

It almost sounds like the question is *should* OpenMCL bother  
providing native SIMD instruction support?  It doesn't seem like it  
would ever generate truly optimal code with so many unknowns at  
compile time without some pretty ugly, non-standard hinting to the  
compiler.  To get the bang from SIMD, wouldn't substantial chunks of  
non-compiler library code (map comes to mind) and data structures  
have to be altered?  Has going the route Apple is pushing make SIMD a  
library issue and provide an optimized method for passing/retrieving  
data (i.e. SIMD-optimized vectors) and use FFI to call the optimized  
routines been considered (and rejected)?  It seems to provide  
relatively cheap support of SIMD across all architectures for the  
cost of FFI interfaces and a specialized data type.

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