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Re: PA64 configure issues
- To: law at cygnus dot com
- Subject: Re: PA64 configure issues
- From: Geoff Keating <geoffk at cygnus dot com>
- Date: Tue, 25 Apr 2000 11:01:49 -0700
- CC: gcc at gcc dot gnu dot org, gdb at sourceware dot cygnus dot com, binutils at sourceware dot cygnus dot com, autoconf at sourceware dot cygus dot com
- References: <11276.956679822@upchuck>
> Date: Tue, 25 Apr 2000 10:23:42 -0600
> From: Jeffrey A Law <law@cygnus.com>
> In general, most developers do not need PA64 capabilities, in fact, using
> PA64 generally results in programs that are larger and slower than PA32
> programs. My current thoughts are to have the GNU tools default to PA32
> and require special options or configure names to enable PA64 capabilities.
This is the approach we use on ppc. The exact same constraints
exist---ppc64 binaries are less compatible, and may not be faster. So
the toolchains default to 32-bit binaries, and switch to doing 64-bit
with the option '-maix64'.
> Right now on a PA64 capable machine config.guess will return something like
>
> hppa2.0w-hp-hpux11.00
> ^
> +------ This indicates the machine has the capability to run PA64
> code.
It turns out to be surprisingly useful to be able to build 64-bit
binaries on a 32-bit machine. Partly this is because AIX can build
shared libraries that contain both 32-bit and 64-bit code, but also
because the 32-bit machines turn out to be faster for compiling on
(the compiler is a 32-bit binary, of course :-).
So on aix/ppc, the toolchain can always build 64-bit binaries when the OS
support for it is there (on AIX 4.3 and higher).
--
- Geoffrey Keating <geoffk@cygnus.com>