1. Floating point hardware
- Posted by rforno at tutopia.com
Jul 31, 2002
Rob:
I am translating REFMAN.DOC into Spanish. I found in a Performance Note that
ex.exe will use routines contained into it to simulate floating point
hardware if not present. It says that these routines may reside in Windows,
implying that this applies to exw.exe. But what about exu/Linux? And what
about forcing the use of FP hardware under exw.ex and exu?
Regards.
2. Re: Floating point hardware
Ricardo Forno writes:
> I am translating REFMAN.DOC into Spanish.
> I found in a Performance Note that ex.exe will use
> routines contained into it to simulate floating point
> hardware if not present. It says that these routines
> may reside in Windows, implying that this applies
> to exw.exe. But what about exu/Linux?
exu uses hardware floating-point instructions.
I assume that if the hardware isn't present, Linux will
emulate f.p. with software, just like Windows does.
In any case, I don't provide you with any f.p. options on Linux.
The percentage of machines that don't have hardware f.p.
is very small and getting smaller.
> And what about forcing the use of FP hardware under exw.ex and exu?
f.p. hardware, if it exists, will be used when you run exw and exu.
You don't have an option. There is nothing to "force".
Regards,
Rob Craig
Rapid Deployment Software
http://www.RapidEuphoria.com
3. Re: Floating point hardware
Robert Craig wrote:
>
> Ricardo Forno writes:
> > routines contained into it to simulate floating point
> > hardware if not present.
> > ...
> > But what about exu/Linux?
>
> I assume that if the hardware isn't present, Linux will
> emulate f.p. with software, just like Windows does.
Yes, Linux and FreeBsd both have f.p. emulation. You might want to check
your kernel/module config to make sure it's either compiled in or loaded
as a module on start-up.
-Ron Tarrant
4. Re: Floating point hardware
- Posted by r.schr at t-online.de
Aug 04, 2002
rforno at tutopia.com wrote:
>
> Oops. I meant force the non-use of FP Hardware, i. e., using emulation to
> avoid the early Pentium fp bug.
My wish would be to force the use of FP hardware. But there could be a
switch (i.e. with FPSOFT) to change this. Have in mind: the FP software
(which is used only under DOS) is in a certain number range not as
accurate as the FP hardware is. Only in case you have not changed the
corrupt Pentium you should use the FP software.
Have a nice day, Rolf
5. Re: Floating point hardware
On 0, rforno at tutopia.com wrote:
>
> Rob:
> I am translating REFMAN.DOC into Spanish. I found in a Performance Note that
> ex.exe will use routines contained into it to simulate floating point
> hardware if not present. It says that these routines may reside in Windows,
> implying that this applies to exw.exe. But what about exu/Linux? And what
> about forcing the use of FP hardware under exw.ex and exu?
> Regards.
>
The glibc library used by Linux has support for floating point
instructions,
and FreeBSD's C Library should have support as well. Since the use of
FP
hardware/software emulation is done via the OS in Windows and the C
Library
under Unix, there is no way to directly force the use of FP hardware
under
exw.exe or exu. There may be workarounds, however (for example
recompling
the Linux kernel with FP software emulation), but since the OS takes
care of
this the programmer doesn't need to worry about it. DOS is the
exception as it
has no support for this directly, requiring the programmers to do this
themselves.
jbrown
P.S. FP emulation is done via the kernel, and not glibc, for Linux. I
don't
know about FreeBSD though.
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