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From: bert@Shiva.COM (Robert D. Vincent)
Newsgroups: comp.sys.nsc.32k
Subject: Running without an FPU
Message-ID: <9009180017.AA19520@Shiva.COM>
Date: 18 Sep 90 00:17:16 GMT
Sender: news@daver.bungi.com
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Approved: news@daver.bungi.com

I've had to struggle a bit, but I've managed to get MINIX up on my pc532
without an FPU. Some of the problems I encountered are:

* The ROM needed a fix to get RUN and STEP to work.
* MINIX saves FPU registers on a task switch
* _begsig also saves FPU registers, causing any process which intercepts
  signals to dump core.
* GCC uses floating point operations in global-alloc.c

So far I've been able to fix these problems in an ad-hoc manner, but I'd 
like to co-ordinate efforts with other FPU-less pc532 owners (if there are
any).
 
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?
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?
3) Are there any free (or nearly so) floating point emulation libraries 
   for the NS32000 series? 
4) Are there other traps I haven't stumbled into yet?
	-bert