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From: dbj.rice@rand-relay@sri-unix.UUCP
Newsgroups: net.unix-wizards
Subject: Re:  What are IOT and EMT instructions?
Message-ID: <4415@sri-arpa.UUCP>
Date: Sun, 21-Aug-83 06:34:16 EDT
Article-I.D.: sri-arpa.4415
Posted: Sun Aug 21 06:34:16 1983
Date-Received: Mon, 22-Aug-83 10:34:56 EDT
Lines: 20

From:  Dave Johnson <dbj.rice@rand-relay>

"IOT and EMT are PDP-11 machine instructions.  On a non-PDP-11 UNIX these
instructions probably don't exist..."

Yes, there are no "IOT" or "EMT" instruction on a VAX, but a SIGEMT may be
generated by the XFC machine instruction.  Although "as" doesn't have a
mnemonic for this instruction, you can still generate it by assembling the
constant 0xfc as a byte.

"in fact, the abort() library function generates a SIGIOT to force a core
dump."

No, on 4.1 BSD at least, abort() generates a SIGILL by executing a "halt"
instruction.  Check /usr/src/libc/sys/abort.s

                                        Dave Johnson
                                        Dept. of Math Science
                                        Rice University
                                        dbj.rice@Rand-Relay