[gambit-list] Re: Implementation of read-ieee-float64

Bradley Lucier lucier at math.purdue.edu
Fri Dec 9 00:21:01 EST 2005


On Dec 8, 2005, at 9:12 PM, Alex Shinn wrote:

> On 12/7/05, Bradley Lucier <lucier at math.purdue.edu> wrote:
>>
>> Gambit 4.0b15 fails some srfi-56 tests because the first instance of
>> 2.0 is not 2; unfortunately, Gambit-C calculates
>>
>> (expt 2.0 -1074)
>>
>> as
>>
>> (/ (expt 2.0 1074))
>
> Hi, thanks for looking into this and getting it working with Gambit.
> The (expt 2.0 ...) form was there for the sake of Bigloo, for which
>
>   (expt N -M) => 0
>
> for all exact integers N, M > 1.

This may not be unreasonable for an implementation without rationals,  
like bigloo, but perhaps it would be better to do an inexact expt in  
this case.

> Choosing between the lesser of two evil^H^H^H^Hbugs,

I'm working on a new expt that trusts libm's pow function more ...

Brad



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