Mailinglist Archive: opensuse (3337 mails)

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Re: [Fwd: Re: [SLE] Real Numbers representation in Tcl language]
  • From: Jerry Feldman <gaf@xxxxxxx>
  • Date: Thu, 13 Apr 2006 10:36:01 -0400
  • Message-id: <200604131036.01776.gaf@xxxxxxx>
On Wednesday 12 April 2006 6:32 pm, Greg Wallace wrote:
> On Wednesday, April 12, 2006 @ 2:30 PM, John E. Perry wrote:
> >Sorry Greg, I forgot the SLE reply-to quirk.
>
> No problem. I didn't realize the program used software to elevate the
> values for ordinates and mantissas beyond the machine's hardware limits.
> Very interesting. I'm obviously way behind the times on how math
> functionality is implemented in the modern PC era! Good info.
This has always been true. Today, 128 bit long doubles are generally done in
software.
Additionally, some IEEE functionality is implemented in software.
For instance, most floating point numbers are stored in normalized format,
but there are numbers greater than 0.0 but less than the minimum normalized
number that generally require software. These are called denormals, and
those are one of the reasons that most compilers generate "fast floating
point" by default because strict IEEE compliance can be very slow.
--
Jerry Feldman <gaf@xxxxxxx>
Boston Linux and Unix user group
http://www.blu.org PGP key id:C5061EA9
PGP Key fingerprint:053C 73EC 3AC1 5C44 3E14 9245 FB00 3ED5 C506 1EA9

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