I was suprised that a -0.1*0 yields a negative zero. Here is a more extensive test (perl 5.10.0 or 5.8.9). Why are we getting a negative fp zero from multiplication by a zero? Is it a bug or a (mis)feature?

perl -e 'for (-2.0,-1.9,-1.5,-1.1,-1.0,-0.9,-0.5,-0.1,-0)
 {$v = $_ * 0; printf("%5s -> %2s,%24.16e\n",$_,$v,$v)}'

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   -2 ->  0,  0.0000000000000000e+00
 -1.9 -> -0, -0.0000000000000000e+00
 -1.5 -> -0, -0.0000000000000000e+00
 -1.1 -> -0, -0.0000000000000000e+00
   -1 ->  0,  0.0000000000000000e+00
 -0.9 -> -0, -0.0000000000000000e+00
 -0.5 -> -0, -0.0000000000000000e+00
 -0.1 -> -0, -0.0000000000000000e+00
    0 ->  0,  0.0000000000000000e+00

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In reply to Negative zero from a multiplication by a zero? by Anonymous Monk

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