[Numpy-discussion] Can we assume both FPU and ALU to have same endianness for numpy ?

Francesc Alted faltet@pytables....
Tue Mar 10 11:13:13 CDT 2009


A Tuesday 10 March 2009, David Cournapeau escrigué:
> Hi,
>
>     While working on portable macros for NAN, INF and co, I was
> wondering why the current version of my code was working
> (http://projects.scipy.org/numpy/browser/trunk/numpy/core/include/num
>py/npy_math.h, first lines). I then realized that IEEE 754 did not
> impose an endianness, contrary to my belief. The macros would fail if
> the FPU and the ALU were using a different endianness. Is this still
> a possibility on the architectures we want to support ?

Could you be more explicit?  Currently, there is only a part of the 
processor that does floating point arithmetic.  In old systems, there 
was in a FPU located outside of the main processor, but in modern ones, 
I'd say that the FPU is always integrated in the main ALU.

At any rate, having an ALU and FPU with different endianess sounds 
*very* weird to my ears.

Cheers,

-- 
Francesc Alted


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