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Author mark.dickinson
Recipients belopolsky, drj, ggenellina, mark.dickinson, vstinner
Date 2008-12-09.21:02:36
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Message-id <1228856557.61.0.544208850404.issue3166@psf.upfronthosting.co.za>
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> floating-point variable "x" has an exact nonnegative integer value 
> between 0 and 2**DBL_MANT_DIG. 

Hmm.  On closer inspection that's not quite true.  After the line

x = x * PyLong_BASE + (dig & (PyLong_BASE - pmask));

x has a value of the form n * pmask, where pmask is a power of 2 and
n is in the range [0, 2**DBL_MANT_DIG).  It's still exactly represented, 
provided that FLT_RADIX is 2.  (It's the multiplications by powers of 2 
that get hairy when FLT_RADIX is 16, since they *can* lose information.)
History
Date User Action Args
2008-12-09 21:02:37mark.dickinsonsetrecipients: + mark.dickinson, belopolsky, ggenellina, vstinner, drj
2008-12-09 21:02:37mark.dickinsonsetmessageid: <1228856557.61.0.544208850404.issue3166@psf.upfronthosting.co.za>
2008-12-09 21:02:36mark.dickinsonlinkissue3166 messages
2008-12-09 21:02:36mark.dickinsoncreate