On Thu, Sep 05, 2002 at 04:54:09PM +0200, Maciej W. Rozycki wrote:
> On Thu, 5 Sep 2002, Hartvig Ekner wrote:
> > I don't know the ultimate reasons why SGI choose ILP32 for n32, but one
> > could certainly be portability.
> It depends on how you define "portability". While it might help some
> broken software, it will hurt good one.
> > As defined, n32 provides all the benefits of 64-bit data (yes, you have
> > to use long long to get to it), and 100% backward compatability with
> So you can't use long to keep a file position pointer (off_t is quite a
> new invention) and have to go for long long, for example? Weird and
> definitely doesn't help portability.
> > o32 sources that assume (sizeof(void *)) = sizeof(long), plus binary data
> Thay should be fixed, instead. Using "void *" as a data container
> doesn't work in general and one who does so should be banished. And the
> other way round, there is no problem -- if one keeps 32-bit pointers in
> 64-bit longs, there is no bit loss.
> > file compatability with o32 as all structures are exactly identical between
> > o32 and n32.
> Why don't use o32 as is then, instead of creating a slightly different
> ABI? If some software needs binary data to be identical, then it has to
> select fixed-size types, e.g. int32_t, explicitly. While int32_t and
> friends are quite a new standard, other ways were used for years to set up
> such aspects, e.g. autoconf, imake, hand-written system-specific
> preprocessor macros, etc., etc.
No - the point is that all data types have the same size in N32. It
was created explicitly as a transitional sop for people who didn't want
to fix their code, but wanted a performance increase from their 64-bit
MontaVista Software Debian GNU/Linux Developer