Subject:
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Re: 8-bit floating-point number representations?
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Newsgroups:
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lugnet.off-topic.geek
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Date:
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Thu, 4 Jan 2001 07:32:16 GMT
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Viewed:
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105 times
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In lugnet.off-topic.geek, Frank Filz writes:
> After thinking about this, I realized most compact binary floating point
> forms don't allow denormalized numbers. The reason is that if one
> assures that all numbers are normalized, the bit to the left of the
> decimal point is always a 1, and therefore need not be stored, thus
> increasing the precision by 1 bit (which will be extremely significant
> for an 8 bit float).
>
> [...snip code...]
Wow, Frank, I didn't know you geeked like that! All right!
> I've probably made some misteaks but the above gives an idea of what
> needs to be done at least.
It past my bedtime, so I'll have to think more about it another time, but
you've definitely given me hope that it could be done pretty efficiently.
As a bonus in this case, the numbers are always non-negative, so that would
mean one more bit for the mantissa. I'm starting to wonder, though, whether
8-bit numbers would actually be faster in the long run than 64-bit double-
precision values -- because once the vector is in memory as a memory-mapped
file, the speed is no longer dependent on the size; with enough RAM, the
entire file would stick around in the filesystem cache, or it could even be
locked and held as a dedicated in-memory resource.
--Todd
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Message has 1 Reply:
 | | Re: 8-bit floating-point number representations?
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| (...) I've been a pretty serious geek, especially with low level stuff like this. My first real job involved developing a Fortran style formatted I/O for the Apple II which involved digging into the the internal guts of Applesoft BASIC so that we (...) (23 years ago, 4-Jan-01, to lugnet.off-topic.geek)
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Message is in Reply To:
| | Re: 8-bit floating-point number representations?
|
| (...) After thinking about this, I realized most compact binary floating point forms don't allow denormalized numbers. The reason is that if one assures that all numbers are normalized, the bit to the left of the decimal point is always a 1, and (...) (23 years ago, 4-Jan-01, to lugnet.off-topic.geek)
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