Messages in this thread | | | Subject | Re: fpu IO port reservation (arch/i386) | From | Andi Kleen <> | Date | 21 Sep 2007 18:22:12 +0200 |
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"Maciej W. Rozycki" <macro@linux-mips.org> writes:
> Hi Peter, > > > Does anybody know why we reserve this range of IO ports for 'fpu'? > > AFAIK from all the IO maps I can find on the internet for various x86 > > chipsets only 0x00f0 is actaully ever used. > > There are two ports used: 0xf0 is the busy latch reset and 0xf1 is the > coprocessor reset. They are legacy ports resulting from the interesting > way the FPU has been wired by IBM in their PC design.
Was it really needed on 386s? I didn't think there was a IBM 386 PC.
> None of them is > used by Linux for i486 and newer systems, which can support the FPU in its > native configuration.
I can remove it from x86-64 at least.
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