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From: akmal@nosc@syte.UUCP
Newsgroups: net.unix-wizards
Subject: exec()
Message-ID: <3876@sri-arpa.UUCP>
Date: Fri, 5-Aug-83 13:02:34 EDT
Article-I.D.: sri-arpa.3876
Posted: Fri Aug  5 13:02:34 1983
Date-Received: Sun, 7-Aug-83 02:03:11 EDT
Lines: 7

The answer to your question is fairly obvious if you have studied the code !
If you look at the bottom of setregs, the PC is set to the entry point for
the code. Thus when you return from the call with an RTI, user execution
commences at the new PC.

Why does that particular section strike you as a treasure hunt ??!! Perhaps
you need to 'C' things better !!