4 hundred quadrillonth?

Lawrence D'Oliveiro ldo at geek-central.gen.new_zealand
Mon May 25 09:52:50 CEST 2009


In message <mailman.702.1243237468.8015.python-list at python.org>, Dave Angel 
wrote:

> Lawrence D'Oliveiro wrote:
>
>> Anybody remember a certain Prof William Kahan from Berkeley ...
>>   
> I remember the professor.  He was responsible for large parts of the
> Intel 8087 specification, which later got mostly codified as IEEE 754.

The 8087 was poorly designed. It was stack-based, which caused all kinds of 
performance problems that never really went away, though I think Intel tried 
to patch over them with various SSE extensions. I believe AMD64 does have 
proper floating-point registers, at last.

Apple's implementation of IEEE 754 was so rigorous that, when Motorola 
introduced the 68881, which implemented a few of the "shortcuts" that Kahan 
reviled in his foreword, Apple added a patch to its SANE library to restore 
correct results, with the usual controversy over whether the performance 
loss was worth it. If you didn't think it was, you could always use the 
68881 instructions directly.




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