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From: jww@sdcsvax.UCSD.EDU (Joel West)
Newsgroups: comp.sys.mac
Subject: Re: MDEF 0 on System 4.1
Message-ID: <4089@sdcsvax.UCSD.EDU>
Date: Wed, 14-Oct-87 10:24:32 EDT
Article-I.D.: sdcsvax.4089
Posted: Wed Oct 14 10:24:32 1987
Date-Received: Fri, 16-Oct-87 00:49:02 EDT
References: <970@mntgfx.MENTOR.COM>
Organization: Palomar Software, Inc., Vista, CA
Lines: 17
Summary: standard unimplemented trap

In article <970@mntgfx.MENTOR.COM>, tomc@mntgfx.MENTOR.COM (Tom Carstensen) writes:
> In looking at the MDEF assembly language, I noticed that it
> checks in a few places for a new trap (calling NGetTrapAddress).
> with the HEX value 9F.  What trap is this?

The next thing it does is call NGetTrapAddress with some other trap
and then compare the two returned addresses (he predicted, not
having looked at the code).  Trap A89F is the standard unimplemented
trap, so if the address of any trap is the same as that for A89F,
there is no such trap.  For example, _PopUpMenuSelect ($A80B) is
only implemented in System 4.1 or later, as is _InitProcMenu ($A808).

This is all covered in the August 1987 MacTutor.
-- 
	Joel West  (c/o UCSD)
	Palomar Software, Inc., P.O. Box 2635, Vista, CA  92083
	{ucbvax,ihnp4}!sdcsvax!jww 	jww@sdcsvax.ucsd.edu