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Re: egcs 2.91.66 ix86 problems...


On Thu, 17 Jun 1999, Geoff Keating wrote:

> > So after reading this thing one clearly gets the impression the saying
> > -mcpu=i486 will affect the scheduler only, while egcs will still generate
> > code that will run on i386, and -march=i486 will actually enable
> > i486-specific instructions.
> > 
> > Well, the cpp does not concur to this idea and because of this the glibc
> > headers that are testing for __i486__ (like the ones that define bswap32
> > and bswap16) are getting confused.
> 
> It would be easy for it to be confused; on powerpc, `-mcpu=601' means
> produce code that runs only on 601, and `-mtune=601' means write code
> that runs on any architecture but is scheduled (and so on) for the 601.
> 
> This is in fact how it works for cpp, too; _ARCH_PWR is defined with
> -mcpu=601, but not defined with -mtune=601.

On the Intel -m486 is documented to do what -mtune=i486 would do, but it
doesn't only that, at least the cpp gets badly confised. Anybody thinks
that this is a problem? The fact that compiling against glibc headers with
-m486 (which is almost everywhere in the Makefiles, btw) can result in a
binary that will not run on i386, while the gcc/egcs documentation stated
for years that this would not happen?

Cristian
--
----------------------------------------------------------------------
Cristian Gafton     --     gafton@redhat.com      --     Red Hat, Inc.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 UNIX is user friendly. It's just selective about who its friends are.


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