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From: davet@oakhill.UUCP (Dave Trissel)
Newsgroups: net.micro.68k,net.micro
Subject: MC68881 Floating-point performance times
Message-ID: <263@oakhill.UUCP>
Date: Mon, 10-Dec-84 05:52:01 EST
Article-I.D.: oakhill.263
Posted: Mon Dec 10 05:52:01 1984
Date-Received: Wed, 12-Dec-84 03:30:11 EST
Reply-To: davet@oakhill.UUCP (Dave Trissel)
Organization: Motorola Inc. Austin, Tx
Lines: 47
Xref: watmath net.micro.68k:480 net.micro:8872
Summary: 

xecuting its instruction stream in parallel.

Operations are carried out in strict accordance with the IEEE
Floating-point Specification (P754) Rev 10.0 and with 80 bits
of precision.  The standard clock rate of 16.666 Megahertz is
assumed and the times are all in microseconds.

INSTRUCTION       Reg-to-Reg   ----------Memory to Reg---------------
			       Single      Double     Extended
FMOVE (in)            1.5       3.0          3.4        3.3
FADD/FSUB             2.8       4.3          4.6        4.5
FSGLMUL               3.1       4.6          ---        ---
FSGLDIV               3.8       5.3          ---        ---
FMUL                  4.0       5.5          5.8        5.7
FDIV                  5.9       7.4          7.7        7.6
FSIN/FCOS            23.0      24.5         24.9       24.8
FSINCOS 1            25.5      27.0         27.4       27.3
FTAN                 27.2      28.7         29.1       29.0
FASIN                33.8      35.3         35.7       35.6
FACOS                35.9      37.4         37.7       37.6
FATAN                22.7      24.2         25.5       24.4

1 This instruction returns BOTH the sine and cosine of a value.

Note that these are only a small portion of functions and instructions
available.  Anyone having times for transcendentals (including square
root) for the National NS32081 would you please post them to me?
If there is enough interest in comparing both chips, I will post
a timing contrast on the net.

Motorola Semiconductor                     Dave Trissel
Austin, Texas          {ctvax,ihnp4,seismo,gatech}|ut-sally|oakhill|davet