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Re: GCC 3.3.5: -march=i586 does not use all pentium FPU instructions
On Fri, Feb 11, 2005 at 04:58:42PM -0000, Dave Korn wrote:
> > -----Original Message-----
> > From: gcc-owner On Behalf Of Jonathan Wakely
> > Sent: 11 February 2005 16:34
>
> > On Fri, Feb 11, 2005 at 04:38:03PM +0100, Sam Lauber wrote:
> >
> > > I think Intel's confusing numbering system has confused
> > > you. All ix86 processors, if the expression
> > > x in first ix86 < x in second ix86
> > > holds true, then second ix86 is compatible. The i586 is
> > > NOT the Pentium.
> >
> > So why does the GCC manual say that -mtune=pentium is equivalent to
> > -mtune=i586 ?
>
> In terms of general terminology, it works like this.
>
> 'Pentium' refers to one cpu and one cpu only: the one introduced by Intel
> after the '486.
>
> i586 refers to all roughly-pentium-equivalent processors of that generation:
> the Pentium itself, the AMD K5, the Cyrix 586, etc.
>
> Likewise for i686 and Pentium Pro / K6 / Cyrix 686, etc.
True, I should have been clearer. I'm aware that "Pentium" (TM) != i586,
but for the OP's purposes -mtune=pentium and -mtune=i586 are the same.
Debating the difference between Pentium, pentium, i586 etc. is off-topic
and that is what I was drawing attention to - GCC doesn't distinguish so
the mail I replied to was unhelpful in making the distinction.
jon
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