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From: lsr@apple.UUCP
Newsgroups: comp.sys.mac
Subject: Re: GetTrapAddress and SetTrapAddress?
Message-ID: <1038@apple.UUCP>
Date: Mon, 15-Jun-87 13:54:33 EDT
Article-I.D.: apple.1038
Posted: Mon Jun 15 13:54:33 1987
Date-Received: Wed, 17-Jun-87 01:31:51 EDT
References: <164500036@uiucdcsb> <164500037@uiucdcsb>
Reply-To: lsr@apple.UUCP (Larry Rosenstein)
Organization: Advanced Technology Group, Apple Computer
Lines: 25

In article <164500037@uiucdcsb> kkim@uiucdcsb.cs.uiuc.edu writes:
>
>    Do you mean the LIMIT that the trap dispatch table can address 
>locations within a  range of only 64K bytes from the beginning of the
>system heap has been LIFTED, and that  the format of the trap dispatch 
>table has been changed.

On the 128K ROMs or later, the trap table contains a full address pointing
to the trap routine.  Therefore the trap routine can be anywhere in memory.

On the older ROMs, the table contained a 16 bit offset from the start of
RAM or ROM; the address of a trap had to be within 64 of the start of RAM or
ROM. 

The change in the trap table is discussed in Inside Macintosh volume 4.

-- 
Larry Rosenstein

Object Specialist
Apple Computer

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