Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!cs.utexas.edu!uunet!fernwood!portal!cup.portal.com!Invader
From: Invader@cup.portal.com (Michael K Donegan)
Newsgroups: comp.sys.mac.programmer
Subject: Re: A-Trap length
Message-ID: <28824@cup.portal.com>
Date: 12 Apr 90 06:50:17 GMT
References: <1645.2610e886@vaxa.uwa.oz> <4598@daffy.cs.wisc.edu>
Organization: The Portal System (TM)
Lines: 14

Copying traps from ROM to RAM?  This is so fraught with danger I can't
believe that you are considering it.  For one thing, getting the trap
address is easy, but it doesn't guarantee that it is in ROM.  Many traps
are patched.  They begin in RAM, wander back to ROM, etc.  And those
patches often depend on the code being in ROM.  So if the trap you are
considering moving calls another trap via the A-trap (instead of just
calling it) the patches that check for things like "Was I called from
MoveWindow?" won't work anymore.  Also many traps use PC-relative data
and will flat fail if you move the code and not the data, too.  Finally and
most obviously, this is not like compiled code where all of one routine is
together in one place.  Heck no!  This is ASSEMBLER and it can go anywhere.
Whatever you are trying to do, there must be a better way.  What ARE you
doing?
	mkd