Re: AMD x86_64 linux binaries for gfortran

[Tim Prince <tprince at computer dot org>]

At 12:21 PM 3/22/2005, Steve Kargl wrote:

> On Tue, Mar 22, 2005 at 09:07:47PM +0100, Fran?ois-Xavier Coudert wrote:
> >
> > 64bits linux). These seems to default integers to 32 bits,
> > if you feel the other behavior (default 64 bits integers) is better I'll
> > be happy to do it, if someone can tell me what is the magic option
> > for configure.
>
> I don't think you want to default to 64 bit integer for
> the default integer kind.  If you do, then this implies
> that we have 64-bit reals for the default real kind and
> then we would need REAL(10) to work for the additional
> kind with higher precision as specified by the standard.
> We have no support for intrinsic procedures with REAL(10),
> nor do we have IO routines.

As these x86-64 machines are designed to take advantage of 32-bit data for 
best performance, and existing 64-bit compilers have 32-bit default kinds, 
this is good advice.  In gcc, only long and pointer types become 64 
bits.  I'd like to see a "64-bit" Windows gfortran as well, and there the 
ABI even more clearly favors 32-bit default data types.  I don't favor 
making gcc for Windows inconsistent with gcc for linux, but let's not go 
out of our way to make gfortran inconsistent with Windows ABI.  There is a 
movement to add a 64-bit integer type to the common MPI implementations, 
but even that isn't there yet.


Tim Prince