Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!gem.mps.ohio-state.edu!ginosko!uunet!mitel!melair!low
From: low@melair.UUCP (Rick Low)
Newsgroups: comp.sys.m68k
Subject: Re: Need help with 68881
Summary: The User's Manual has this info.
Message-ID: <283@melair.UUCP>
Date: 18 Aug 89 19:53:27 GMT
References: <1135@kuling.UUCP>
Organization: MEL Defence Systems Ltd., Ottawa, Canada
Lines: 48

In article <1135@kuling.UUCP>, jonasf@kuling.UUCP (Jonas Flygare) writes:
> I am writing some programs using the 68881, and have a small problem..
> I have tried to get documentation on the 68881, and so far the best one
> is the technical summary BRE265R3.

Try to get
	MC68881/MC68882 Floating-Point Coprocessor User's Manual,
	Englewood Cliffs, NJ, USA 07632, Prentice Hall Inc., 1987.
	ISBN 0-13-566936-7
I got mine from the local Motorola office.

> On the front page it states that
> the FPU have 22 constants available in the on-chip ROM.
> "How nice I thought, _just_ what I need.." However, I cannot find any 
> reference to HOW I access those available constants.. ;-)
> Anyone know how? Also, pointers to better documents describing the FPU 
> would be appreciated. email preferred.

The FMOVECR instruction (Move Constant ROM) can load the following
constants from 68881 ROM into a coprocessor register:

	pi
	log10(2)
	e
	log2(e)
	log10(e)
	0.0
	ln(2)
	ln(10)
	10^n, n=0,1,2,4,8,16,32,64,128,256,512,1024,2048,4096

That makes 22 constants.

> Thanks in advance.-- 
> Jonas Flygare (aka Flax)        |If God had wanted me to have opinions he 
> email: jonasf@kuling.UUCP       |would have given me UseNet access..
> real:  Vaktargatan 32 F:621     |
>        S-754 22 Uppsala Sweden  |

Rick Low
MEL Defence Systems Limited, Ottawa, Canada
+1 613 836 6860
mitel!melair!low@uunet.UU.NET
-- 
Rick Low
MEL Defence Systems Limited, Ottawa, Canada
+1 613 836 6860
mitel!melair!low@uunet.UU.NET