[Python-Dev] Python-acceleration instructions on ARM

["Martin v. Löwis"]

Antoine Pitrou wrote:
> Martin v. Löwis <martin <at> v.loewis.de> writes:
>> - efficient array indexing: they give shift-and-index back to
>>   Thumb mode, for a shift by 2, allowing to index arrays with
>>   4-byte elements in a single instruction (rather than requiring
>>   a separate multipy-by-four). Again useful for JIT of array
>>   access instructions, not applicable to Python - although it
>>   would be nice if the C compiler knew how to emit that.
> 
> This could be used in PyTuple_GetItem and PyList_GetItem, no?
> (assuming Thumb has 4-byte pointers)

Yes - but it would require an assembly version of these functions;
I'm skeptical that the savings would be measurable (given that there
is also the type check and the range check).

OTOH, PyTuple_GET_ITEM could probably be implemented as
inline assembly.

Regards,
Martin