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Re: integer Vs floating point efficiency?

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Gordon Sande wrote:

> On 2012-12-01 08:41:21 -0400, Rui Maciel said:
>
> Instruction timings etc are to be found in the processor's data sheets.
> Ask the manufacturer of one. The web sites will have copies or request
> pages.

I've followed your advice, and I'm in the process of digesting AMD and 
Intel's docs that cover this subject.  If anyone is interested, the 
documents are available at:

http://support.amd.com/us/psearch/Pages/psearch.aspx?type=2.1%3b2.12&product=2.1.2&contentType=Tech%20Doc%20Processor
http://www.intel.com/content/www/us/en/processors/architectures-software-
developer-manuals.html


Unfortunately, the information isn't compiled or easily accessible.  To make 
matters worse, I've stumbled on a claim that Intel's docs have been 
"incomplete and full of errors", which isn't very reassuring.  

Nevertheless, some info on this subject has been compiled by third parties, 
such as the following article:

http://www.agner.org/optimize/instruction_tables.pdf


As should be expected, latency varies with the make and model of the 
processor, and instruction latency alone doesn't say everything there is to 
say (or, possibly, anything) about the inherent efficiency of integer Vs 
floating point data types. In addition, there are more than a way to skin 
some numerical cats with the AMD64 platform, which adds to the complexity of 
this issue.

Nevertheless, from what I gathered so far it appears that, in general, 
integer operations do present a small, but possibly entirely meaningless, 
efficiency advantage.


Rui Maciel

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Thread

integer Vs floating point efficiency? Rui Maciel <rui.maciel@gmail.com> - 2012-12-01 12:39 +0000
  integer Vs floating point efficiency? Rui Maciel <rui.maciel@gmail.com> - 2012-12-01 12:41 +0000
    Re: integer Vs floating point efficiency? Herman Rubin <hrubin@skew.stat.purdue.edu> - 2012-12-02 23:10 +0000
      Re: integer Vs floating point efficiency? Robin Vowels <robin.vowels@gmail.com> - 2012-12-02 16:36 -0800
    Re: integer Vs floating point efficiency? Rui Maciel <rui.maciel@gmail.com> - 2012-12-03 10:03 +0000
  Re: integer Vs floating point efficiency? BGB <cr88192@hotmail.com> - 2012-12-01 16:49 -0600
  Re: integer Vs floating point efficiency? "Chris Uppal" <chris.uppal@metagnostic.REMOVE-THIS.org> - 2012-12-03 10:22 +0000

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