68881 Floating Point Speed Increase on Sun 3/60
Wayne Little
rwl at umree.ee.umr.edu
Fri Sep 22 03:09:08 AEST 1989
One of the professors here at UMR discovered that he gained a 5 times
performance increase on some of his floating point intensive code with
complex numbers by using in-line expansion.
The problem was with the *humongous* amount of stack traffic that was
being generated by the 68881 coprocessor calls.
The fix is to designate the inline expansion library for the 68881 on the
compile line -
e.g.
f77 -c -f68881 code.c -O code /usr/lib/68881/libm.il
The problem and solution are described in detail in section G
(Assembly-Level In-line Expansion) of Sun's Floating-Point Programmer's
Guide, pp. 105-113.
I hope this will be of help to others.
-- Wayne Little Internet: rwl at ee.umr.edu UUCP: uunet!umree!rwl
Phone: (314) 341-4546 USPS: Univ. of Missouri-Rolla, EE Dept., Rolla, MO 65401
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