cvs commit: src/sys/ia64/include float.h

Peter Jeremy peterjeremy at optushome.com.au
Tue Apr 1 12:05:10 PST 2003


On Tue, Apr 01, 2003 at 05:24:40PM +0200, Alexander Leidinger wrote:
>On Mon, 31 Mar 2003 18:20:23 +1000
>Peter Jeremy <peterjeremy at optushome.com.au> wrote:
>
>> It's not clear exactly what this program is intended to test.
>
>We noticed that icc does use other values for LDBL_MIN than we do, and
>instead of just thinking that Intel does it right I wanted to verify it.
>So I started with tests for float and double.

The actual digit string forming the constants is not especially
important - as long as the compiler interprets that string as the
correct FP value.  There are a number of test programs intended to
verify correct FP behaviour by the CPU and compiler floating around on
the net - look at NETLIB or Prof W. Kahan's web site.  (I don't have
the URL's immediately to hand).

>> > The *_MIN
>> >values (or my test program) at least on i386 machines are wrong.
>> 
>> The *_MIN values represent the greatest negative value, not the
>> smallest positive value.
>
>*_MIN _is_ the smallest positive value... but the normalized one, not
>the denormalized one I use.

Mea culpa.  I must have disconnected my brain when I was writing that :-(.

Peter


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