clipka <nomail@nomail> wrote:
> And you can compile a Linux kernel that doesn't
> include support for them either.

  I can compile a Linux kernel that doesn't run at all. What does that prove?

> > The OS plays no role in this process.

> It does. As long as it invokes x87 FPU commands in an attempt to store their
> contents for a task switch, you can't strip those commands from your CPU,
> because it would break the OS.

  And as long as the OS is run on a system with FPU and with programs using
the FPU, the OS cannot drop support. It's that simple.

  As I have said like a dozen times, it makes absolutely no sense for an OS
to drop support for the FPU if the computer has one.

  The OS does *not* play any role in the migration from FPU to SSE.

> > > We're not talking abount months here. We're talking about years. Lots of.
> >
> >   And exactly how does the OS drop support for the FPU gradually, during
> > the years?

> Don't ask me.

  I'm asking you because you said it.

> Ask Microsoft, Apple, the Linux community, and Intel and AMD.

  They are not dropping support for the FPU in their OS, so why should
I ask them? Why are they not dropping it? I have repeated it a dozen of
times already: It doesn't make any freaking sense. If the hardware has
an FPU, the OS supports the FPU, period.

  You can't "migrate" the OS to "not support the FPU" over several years.
It either supports it or doesn't. There's no middle ground.

> I'd say: Deprecate x87 FPU use; encourage compiler vendors to default to not
> using it; introduce new OS API calls that do no longer use x87 FPU registers
> for parameter passing (if applicable); deprecate the old API calls; deprecate
> x87 FPU use, deprecate it again and again

  Which is completely different from the OS refusing to run software which
uses the FPU.

> - and then ultimately release a new
> version that just doesn't support it anymore.

  Which would be absolutely nonsensical in a computer with a FPU.

  What are they going to do? Pop up an error dialog saying "sorry, although
this computer does have a FPU, I'm not going to allow you to use it, tough
luck"? Haha.

  How many times do I have to repeat myself? It doesn't make any sense.

> By that time - to mention it again - the percentage of software actually using
> the x87 FPU will have diminished. That is the "gradual" part of this phasing
> out.

  Even if there's 0 new software which uses the FPU, if the OS is run on
a computer with an FPU, it makes absolutely no sense not supporting it and
actively boycotting any software which tries to use it.

-- 
                                                          - Warp

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