...but why?
Probably because of something that isn't in your post. See sscce.org for details.

Here's one example: 

$ perl -e 'use integer; print -8 + -15 * 0.5, "\n";'

[download]
But I don't really want to guess.

In reply to Re: Floating point hell by Anonymous Monk
in thread Floating point hell by DcmbrAgnt

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