[comp.sys.sun] undump and the fpa

gropp-bill@yale.arpa (Bill Gropp) (11/23/88)

I am trying to use undump on a program that uses the fpa.  Undump works
fine on the version of this program that uses the 68881, but seems to hang
the first time the fpa is used.  I'm actually not surprised at this, since
the fpa is a device (rather than a tightly coupled co-processor like the
68881), and is probably accessed by doing some open-file like operation.
My question is, what do I need to do in a program to re-initialize the fpa
so that my undump'ed program will work?  I've checked the Floating Point
Programmer's Guide, as well as the fpa manual, without finding what I
need.

Bill Gropp

henry@uunet.uu.net (12/10/88)

>I am trying to use undump on a program that uses the fpa.  Undump works
>fine on the version of this program that uses the 68881, but seems to hang
>the first time the fpa is used.  I'm actually not surprised at this, since
>the fpa is a device...and is probably accessed by doing some open-file
>like operation.

No, the FPA looks like a bunch of really strange memory locations off in a
funny corner of the address space, plus occasional signals.  Two things
come to mind:  (1) saving FPA state (don't know if SunOS does this, and
doubly don't know if undump is smart enough to set things up to restore
it);  (2) setting up the FPA signal handler, which is an absolute
necessity (see the Floating Point Programmer's Guide).

	Henry Spencer at U of Toronto Zoology
	uunet!attcan!utzoo!henry henry@zoo.toronto.edu