Path: utzoo!attcan!uunet!wuarchive!usc!julius.cs.uiuc.edu!apple!voder!nsc!taux01!amos
From: amos@taux01.nsc.com (Amos Shapir)
Newsgroups: comp.sys.nsc.32k
Subject: Re: Running without an FPU
Message-ID: <4623@taux01.nsc.com>
Date: 18 Sep 90 12:07:41 GMT
References: <9009180017.AA19520@Shiva.COM>
Organization: National Semiconductor (IC) Ltd, Israel, Home of the Series 32000
Lines: 36
X-Hdate: 28 Elul 5750

[Quoted from the referenced article by bert@Shiva.COM (Robert D. Vincent)]
> 
>I have several questions for the NS32K wizards out there:
>
>1) Is there some way to reliably detect the physical presence or absence 
>   of an FPU?

Put your hand into the box and feel the socket... Is that physical enough? :-)
Seriously, the 532 will get stuck if it tries to access a non-existent FPU
and the F bit in the CFG is set.  The only way to know whether the CFG
should be set is by a jumper or a switch (assuming whoever takes the FPU
out also remembers to put the jumper in or flip the switch).

>2) Is there any way a user process can read the state of the F bit in 
>   the CFG register, given that SPRi CFG,Rn is a privileged instruction?

Make a special system call, or have the kernel put a copy of the CFG
in a global variable.

>3) Are there any free (or nearly so) floating point emulation libraries 
>   for the NS32000 series? 

None that I know of, but there may be some for other processors which
are rather straightforward to convert.

>4) Are there other traps I haven't stumbled into yet?

I don't know much about Minix, but on Unix there aren't many utilities that
need FP; those who do are sure to let you know...

Good luck!

-- 
	Amos Shapir		amos@taux01.nsc.com, amos@nsc.nsc.com
National Semiconductor (Israel) P.O.B. 3007, Herzlia 46104, Israel
Tel. +972 52 522255  TWX: 33691, fax: +972-52-558322 GEO: 34 48 E / 32 10 N