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From: nerd@percival.UUCP (Michael Galassi)
Newsgroups: comp.arch
Subject: Re: What should be in hardware but isn't
Message-ID: <927@percival.UUCP>
Date: Sat, 10-Oct-87 00:18:22 EDT
Article-I.D.: percival.927
Posted: Sat Oct 10 00:18:22 1987
Date-Received: Mon, 12-Oct-87 03:20:30 EDT
References: <30382@sun.uucp>
Reply-To: nerd@percival.UUCP (Michael Galassi)
Organization: Percy's UNIX, Portland, OR.
Lines: 23

In article <30382@sun.uucp> lyang@sun.UUCP (Larry Yang) writes:
...
>I'll have to admit that I haven't designed any floating point arithmetic,
>so if I'm way off base, someone please correct me.

I've designed some floating point routines for the 68k and can testify that
it is not overliy dificult, the hard part being detirminig what ranges of
inputs are valid and verifying that the function is well behaved over all
that range.

>... But it would seem that much would be gained
>from the chip design/fab/test area if the sweating over complex functions
>would be moved to the software realm.

The bigest advantage I see in using microcode to do the FP is that you
save the memory references while the computation is being done freeing
up the bus for the likes of dma, concurrent cpu operations, and any other
bus master's intervention.
-- 
If my employer knew my opinions he would probably look for another engineer.

	Michael Galassi, Frye Electronics, Tigard, OR
		...!tektronix!reed!percival!nerd