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 Trouble on Compaq Deskpro 386: make gives floating point exception
I've installed the A, D, and parts of N and AP Slackware disk sets
on a Compaq 386. When I try to run make (either make config to remake
the kernel or just make on a random Makefile) I get a floating point
exception.  I just fetched slackware last week so presumably have
2.2 and the kernels I've tried this with are 1.2.3 and 1.2.5.
My libc and my make binary are identical to those on an Intel 486
machine that works fine.

Which suggests . . . hardware compatibility problems!  I get the:

No BIOS32 extensions present.

complaint on bootup with the 1.2.3 kernel (and have no idea
what this means) and with both kernels I see the following report:

Checking 386/387 coupling . . . Ok, fpu using old IRQ 13 error reporting
Checking hlt instruction . . . Ok.

Has anyone been peculiar enough to install on a Compaq DeskPro
386 before?  Does anyone know of a way to "check" my FPU (from DOS
or Linux) or is there a way to force Linux to ignore the hardware FPU
and use the software emulation?  Any hints profoundly appreciated!

Heather Sherman
heat...@cco.caltech.edu



 Mon, 06 Oct 1997 03:00:00 GMT   
 Trouble on Compaq Deskpro 386: make gives floating point exception
In article <3n49mn$...@gap.cco.caltech.edu>,
Heather L. Sherman <heat...@cco.caltech.edu> wrote:

Some suggested that I pull out the FPU---which I did, and learned it
was a 287 FPU (apparently Compaq was Very Eager to get their 386
machines to market and didn't wait for the 387 chips). "make" is
Much happier now.  

Now . . . I wonder what I'll stumble into next?

Heather Sherman



 Tue, 07 Oct 1997 03:00:00 GMT   
 Trouble on Compaq Deskpro 386: make gives floating point exception
Heather L. Sherman (heat...@cco.caltech.edu) wrote:

: <sniped>

: Which suggests . . . hardware compatibility problems!  I get the:

: No BIOS32 extensions present.

: complaint on bootup with the 1.2.3 kernel (and have no idea
: what this means) and with both kernels I see the following report:

: Checking 386/387 coupling . . . Ok, fpu using old IRQ 13 error reporting
: Checking hlt instruction . . . Ok.

: Has anyone been peculiar enough to install on a Compaq DeskPro
: 386 before?  Does anyone know of a way to "check" my FPU (from DOS
: or Linux) or is there a way to force Linux to ignore the hardware FPU
: and use the software emulation?  Any hints profoundly appreciated!

Hello,

What do you mean by "peculiar enough"? :)

Anyway, the first thing to get straight is whether or not you really have
an 80387 math coprocessor. You may open up the case and check the actual
socket (to be absolutely sure) or maybe just run the Compaq setup/diagnostics
software and see what it says (to be reasonably sure). Even if an 80387 math
coprocessor is present you should check its speed (which is stamped on top
of the chip) and make sure that it matches the processor speed (this may be
a problem if the coprocessor was installed after the system was purchased
from Compaq). Also, hopefully, both the processor and the math coprocessor
will be "Intel inside" chips and not clones (e.g., the Weitek math
coprocessor). Please note, I'm not saying that Intel is necessarily better
but compatibility is rarely a problem.

Now some possibilities:

    (i)   If no coprocessor is installed but the kernel seems to think
          that one is present (by the boot messages) then there may be
          an interrupt conflict of some kind. You can check out this
          kind of stuff with the Compaq Diagnostics, Manifest (from QEMM),
          ASQ (from 386MAX), or MSD (from MS-Windows).
    (ii)  To disable checking for and using an FPU, you may have to pick
          another boot kernel (I don't recall offhand which ones contain
          FPU support and which ones don't but check the docs). Alternatively,
          at the lilo boot prompt type something like (replacing "vmlinuz"
          with the name of your boot kernel):

          boot: vmlinuz no387

          The "no387" option should cause the kernel to ignore an 80387
          even if it is present.

Good luck.

                                                Lawrence



 Tue, 07 Oct 1997 03:00:00 GMT   
 
   [ 3 post ] 

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