[Ecls-list] wrong value for (float-sign -0.0)

[Juan Jose Garcia-Ripoll]

On Sun, Sep 28, 2008 at 9:13 PM, Raymond Toy <toy.raymond at gmail.com> wrote:
>> | Gabriel Dos Reis wrote:
>> | > Hi Juanjo,
>> | >
>> | >   ECL reports wrong value for the sign of -0.0.
>
> Since ecl compiles to C, it might be difficult to get signed zeroes to
> work out right.

Seems to be the case. If you look at the implementation of float-sign,
we get the sign just by comparing against 0

	case t_singlefloat:
		negativep = sf(x) < 0; break;
	case t_doublefloat:
		negativep = df(x) < 0; break;

This does not seem to be the right way to get the sign :-/ I have
changed the code now to use the macro signbit() where available. I
also had to change the reader and other numeric functions to allow
creating signed zeros. Now things are better: -0.0 and 0.0 can be read
and printed, they do not compare EQL but are the same under numeric
comparison with #'=

Juanjo

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Instituto de Física Fundamental, CSIC
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