From: utzoo!decvax!harpo!seismo!hao!hplabs!sri-unix!ica!dave@Ucla-Security
Newsgroups: net.unix-wizards
Title: Why won't my 11/23 do long division?
Article-I.D.: sri-arpa.930
Posted: Sat Apr  2 15:42:00 1983
Received: Wed Apr 20 05:01:28 1983

From:  David Butterfield <ica!dave@Ucla-Security>

I ran into this last year.  The divide routine does a divide instruction
and then looks to see if it worked (condition codes or something).  On the
11/45, the dividend was left untouched if it didn't work.  On the 11/23
it was garbaged.  (The processor handbook leaves it "undefined").  The
ldiv routine assumes and depends on the value being untouched.  If you
save the value and restore it in the cases that don't work, it will
suddenly start working.

I no longer run a 23 and that is why this message is so vague.  If you
are interested and can't figure it out, send me a message and I will
see about digging out the code.

Dave