Article View: comp.sys.atari.st
Article #33722Re: To Fix or Not To Fix (Really: applying patches to OS)
From: Steven Grimm
Date: Mon, 22 Aug 1988 22:09
Date: Mon, 22 Aug 1988 22:09
21 lines
1651 bytes
1651 bytes
In article <524@nikhefh.hep.nl> gert@nikhefh.hep.nl (Gert Poletiek) writes:
>Look at the way things are organized in the Macintosh OS. All system traps
>are routed by a trap address table (just like in GemDos). The subtle
>difference with GemDos is that the trap address table is located somewhere in
>RAM, not ROM. (Well, it is copied from ROM to RAM at system boot time).
The ST's trap vectors are in RAM, too. In fact, I don't know of *ANY* 68xxx
box that doesn't have them in RAM. Their locations are down in low memory
($60 or thereabouts, I don't remember exactly...) You have to be in supervisor
mode to write to them, but they can certainly be changed. I've done it lots
of times.
>The Mac OS has two calls (GetTrapAddress and SetTrapAddress) which get and
>set a trap vector in the traps table (resp).
Try looking up Setexc() in your XBIOS manual.
---
These are my opinions, and in no way reflect those of UCSC, which are wrong.
Steven Grimm Moderator, comp.{sources,binaries}.atari.st
koreth@ssyx.ucsc.edu uunet!ucbvax!ucscc!ssyx!koreth
Technical Details
Message-ID:
<4582@saturn.ucsc.edu>Path:
arc1-ca.pugleaf.net!utzoo!utgpu!water!watmath!clyde!att!alberta!ubc-cs!uw-beaver!mit-eddie!bloom-beacon!apple!bionet!ig!agate!saturn!ssyx!korethReferences:
<635@ihnet.ATT.COM> <383@snjsn1.SJ.ATE.SLB.COM> <1224@netmbx.UUCP> <524@nikhefh.hep.nl>Show Full Headers
Complete Article Headers
Path: arc1-ca.pugleaf.net!utzoo!utgpu!water!watmath!clyde!att!alberta!ubc-cs!uw-beaver!mit-eddie!bloom-beacon!apple!bionet!ig!agate!saturn!ssyx!koreth From: koreth@ssyx.ucsc.edu (Steven Grimm) Newsgroups: comp.sys.atari.st Subject: Re: To Fix or Not To Fix (Really: applying patches to OS) Message-ID: <4582@saturn.ucsc.edu> Date: 22 Aug 88 22:09:37 GMT References: <635@ihnet.ATT.COM> <383@snjsn1.SJ.ATE.SLB.COM> <1224@netmbx.UUCP> <524@nikhefh.hep.nl> Sender: usenet@saturn.ucsc.edu Reply-To: koreth@ssyx.ucsc.edu (Steven Grimm) Organization: The Mad Scientists' Guild Lines: 21