[m-rev.] diff: fix Pentium 4 recognition bug

Fergus Henderson fjh at cs.mu.OZ.AU
Sun Apr 15 04:10:21 AEST 2001


On 10-Apr-2001, Tyson Dowd <trd at cs.mu.OZ.AU> wrote:
> Branches: main release
> 
> Fix CPU recognition problems with the Pentium 4.
> 
> The P4 reports its CPUID as "15" which is pretty unexpected
> as previously Intel chips used numbers such as "4", "5" and "6".
> Many scripts assumed the pattern i?86 or i[345678]86 would match
> x86 chips.
> 
> The result of mis-identifying the chip is generally failure to compile,
> and even if you do hack around the compilation problems it will almost
> certainly fail to build the garbage collector correctly.

Actually the Boehm GC configuration's is all done by

	#ifdef __i386__

and the like -- it does not use configure or autoconf at all.

The result of mis-identifying the chip shouldn't be failure to compile,
I think.  What ought to happen is that it should build in grade none.gc
rather than asm_fast.gc.  If it is failing in some other way, I'd be
interested in knowing the symptoms.

> config.guess:
> config.sub:
...
> 	Replace i?86 with i*86, and i[345678]86 with i[0-9]*86.

For config.guess and config.sub, I think we should consider following a
similar policy to the one adopted by GCC
(<http://gcc.gnu.org/codingconventions.html>):

 | Upstream packages
 | 
 |    Some files and packages in the CVS tree are imported from elsewhere,
 |    and we want to minimize divergence from their upstream sources. The
 |    following files should be updated only according to the rules set
 |    below:
 |      * config.guess, config.sub: The master copy of these files is at
 |        ftp://ftp.gnu.org/pub/gnu/config. Proposed changes should be
 |        e-mailed to config-patches at gnu.org. Only after the change makes it
 |        to the FTP site should the new files be installed in the GCC CVS
 |        tree, so that their version numbers remain meaningful and unique.
 |        Don't install the patch, install the whole file.

In particular, your change to config.guess and config.sub
is causing me trouble because I want to update those files
to the latest version so that they support Mac OS X (Darwin).
But the latest version doesn't have your Pentium 4 patch.

I'll update them to the latest versions and then merge in your changes.

-- 
Fergus Henderson <fjh at cs.mu.oz.au>  |  "I have always known that the pursuit
                                    |  of excellence is a lethal habit"
WWW: <http://www.cs.mu.oz.au/~fjh>  |     -- the last words of T. S. Garp.
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