Re: IEEE128 binary float to decimal float conversion routines

[Christoph Lauter <christoph.lauter@lip6.fr>]

Hi everyone,

Joseph Myers wrote on 11/16/2015 07:24 PM:

> The BID conversions between binary and decimal float involve several MB of
> tables (whereas libgcc DPD conversions go via strings).  Several MB of
> tables are not of course needed; if doing correctly-rounded conversions
> (required for IEEE 754 conformance) there's a speed/space trade-off in how
> much precomputed data you use versus how much computation you do at
> runtime, and it's up to you what you think the right trade-off for powerpc
> is.
>

For what it's worth: some colleagues of mine and myself have recently 
published a paper on exact binary-to-decimal conversions between all 
IEEE754 formats, assuming BID as the encoding for decimal. None of the 
algorithms we proposed uses a table larger that a couple of dozens of 
kilobytes. Converting between binary and decimal FP with correct 
rounding is essentially the same problem, so people might wish to have a 
look at these results:

> http://www.computer.org/csdl/trans/tc/preprint/07271015-abs.html

Best regards,

Christoph Lauter

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Christoph Lauter
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