Bug#268757: gcc-3.4-doc: x86_64 -march=*, -m64 option documentation needs clarification
Karl Hegbloom writes:
> On Sat, 2004-11-13 at 08:26 +0100, Matthias Klose wrote:
> > > `-m32'
> > > `-m64'
> > > Generate code for a 32-bit or 64-bit environment. The 32-bit
> > > environment sets int, long and pointer to 32 bits and generates
> > > code that runs on any i386 system. The 64-bit environment sets
> > > int to 32 bits and long and pointer to 64 bits and generates code
> > > for AMD's x86-64 architecture.
> > >
> > > It is not clear in the above paragraph whether -m64 implies -march=k8
> > > or what. It probably should not... I am not an expert, that's why I
> > > went to the manual. Can you please fix it?
> >
> > GCC never turns something on, which you don't explicitely specify on
> > the command line. Not sure how you want the documentation be changed.
> > -m64 turns on the common subset for all x86-64 architectures,
> > specifying -march=k8 turns on k8/opteron specific features,
> > -march=nocona turns on some P4/64 Nocona specific features.
> >
>
> Well, there. That's exactly the kind of clarification needed in the
> manual. Somewhere in there it should say that.
ok, I added a note to README.Debian, as the biarch setup for ix86 is
Debian specific.
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