Warp <war### [at] tagpovrayorg> wrote:
>   How many times do I have to repeat myself? It doesn't make any sense.

How long do I have to repeat myself: They're gonna do it some day.

Maybe that'll be the day when they introduce a whole new generation of CPUs
which is no longer compatible to x86 at all, but the day will come.

And they're pondering the idea (or at least have pondered it some time like
beginning of 2008) of dropping the x87 FPU support earlier. I have no idea why
(except wild guesses), but it must have went through their heads.

So all I'm saying here is: Make your software ready for it if it doesn't really
need the FPU. And if AMD is right in that it's not a loss but actually even a
gain, then all the more reason to do so.

That's the bottom line of it. No more, and no less.

All I can give you regarding the "why" is some wild guesses, and they *do* make
*some* sense. It's not *total* bullshit.

>   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.

I repeat, it *does* make *some* sense (I'm not saying it makes *enough* sense):

- There *may* be reasons for chip manufacturers to want to get rid of the x87
FPU in their CPU design. It's complex, and may be in the way for optimizations
of other components. So holding on to the FPU may actually be a performace
problem for *all* software that *does* fine without it or at least *could*
(which I bet is the vast majority).

- You can't strip the x87 FPU off the CPU unless the OS are ready for it, for
about the same reason that you (to some degree undoubtly righteously) argue
that you can't just strip FPU support off the OS.

- The OS *may* not be ready for it unless it itself has totally dropped the x87
FPU support (e.g. due to FPU commands that it may have to issue during task
switching, which may cause a mess on a CPU that doesn't support the x87 FPU)

So we *may* be talking about a way to achieve some significant additional
speedup for 99% of the software that will be out there in, say, 5 years.

If that is the case, I would see that as enough reason to break a few other
pieces of software.


BTW, your claim that you can get every old stuff to run on Vista is BS. Think
for example about the numerous DOS games, which are being "actively boycotted"
and denied direct access to hardware when run under modern OS. And other
software suffered the same issues. Why? Because there was a benefit to be
gained - in that case in terms of stability. Would you say that was a wrong
move?

I'm glad Windows is as stable as it is. (Which is not to say that I praise it
for exceptional stability, but stability back then was far worse.)

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