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From: joel@gould9.UUCP (Joel West)
Newsgroups: net.micro.68k
Subject: Sun-3 floating point
Message-ID: <196@gould9.UUCP>
Date: Mon, 2-Dec-85 18:50:46 EST
Article-I.D.: gould9.196
Posted: Mon Dec  2 18:50:46 1985
Date-Received: Tue, 3-Dec-85 20:22:24 EST
Organization: CACI, Inc. -- La Jolla, Calif.
Lines: 27
Keywords: binary compatibility

This is probably a trivial question -- I don't currently have a 
Sun-3, but may evenutally port software to one.

I understand two Sun-3 configurations are distinct in their 
approach to floating point arithmetic:
	* 68020 + 68881
	* 68020 + Weitek (?) FP board
The second is somewhat faster and is expected to be more popular, I'm told.

Are executables for these two variants binary compatible, i.e., does 
the compiler have to know what machine it is targetting?  If so, I 
assume this means the FP board is emulating the 68881 instruction set, 
or some such.

The machine-language equivalent of the following VAX sequence for one
or both configurations would be appreciated.

	/*	A = B * C + D  */
		movd	B,r0
		muld2	C,r0
		addd2	D,r0
		movd	r0,A
-- 
	Joel West	 	(619) 457-9681
	CACI, Inc. Federal, 3344 N. Torrey Pines Ct., La Jolla, CA  92037
	{cbosgd,ihnp4,pyramid,sdcsvax,ucla-cs}!gould9!joel
	gould9!joel@nosc.ARPA