Re: Parsing timestamps?

On 22/07/2025 6:28 am, Paul Rubin wrote:

dxf <dxforth@gmail.com> writes:

AFAICS IEEE 754 offers nothing particularly useful for the end-user.
Either one's fp application works - or it doesn't.  IEEE hasn't
changed that.

 
The purpose of IEEE FP was to improve the numerical accuracy of
applications that used it as opposed to other formats.
 

IEEE's relevance is that it spurred Intel into making an FPU which in
turn made implementing fp easy.

 
Exactly the opposite, Intel decided that it wanted to make an FPU and it
wanted the FPU to have the best FP arithmetic possible.  So it
commissioned Kahan (a renowned FP expert) to design the FP format.
Kahan said "Why not use the VAX format?  It is pretty good".  Intel said
it didn't want pretty good, it wanted the best, so Kahan said "ok" and
designed the 8087 format.
 
The IEEE standardization process happened AFTER the 8087 was already in
progress.  Other manufacturers signed onto it, some of them overcoming
initial resistance, after becoming convinced that it was the right
thing.
 
http://people.eecs.berkeley.edu/~wkahan/ieee754status/754story.html

There's nothing intrinsically "best" in IEEE's format.  Best product
on the market is what Intel wanted.  It had been selling AMD's 9511
single-precision FPU under licence.  As Kahan says, wind of what Intel
was doing got out and industry's response was to create a standard
that even Intel couldn't ignore.