unsigned int assigned to double

[Chris Torek]

>In article <5020 at nsc.nsc.com> andrew at nsc.nsc.com (Andrew Lue) writes:
>>unsigned int ui = 0xf0000000;
>>double d = ui;

In article <414 at vsi.UUCP> sullivan at vsi.UUCP (Michael T Sullivan) writes:
>Why leave the decision up to the compiler writers?  Cast ui:
>
>	d = (double)ui;
>
>Don't rely on what you think may happen if the compiler happens to be
>what you expect it to be.

I expect the C compiler to implement the C language.  If it does not,
then perhaps nothing I add will help.  And indeed, in this case, since
the semantics of a cast are precisely the same as those of assignment
to an unnamed temporary variable of the type of the cast, all this does
is change a conversion from unsigned to double into a conversion from
unsigned to double, and

	d = (double)ui;

still fails under 4.1BSD.

If you really need to work around the bug, try

	d = (int)ui < 0 ? (int)ui + 4.294967296e9 : (int)ui;

Better yet, go fix the compiler.  What, your vendor `forgot' to
provide compiler sources? :-(
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain:	chris at mimsy.umd.edu	Path:	uunet!mimsy!chris