Article View: comp.os.msdos.programmer
Article #3958Re: stealing an interrupt
From: Kevin Schmidt
Date: Tue, 18 Dec 1990 16:38
Date: Tue, 18 Dec 1990 16:38
36 lines
1983 bytes
1983 bytes
In article <90351.150210TOMIII@MTUS5.BITNET> TOMIII@MTUS5.BITNET (Thomas Dwyer III) writes:
>Hi there. Would some kind soul please tell me why my machine hangs when
>I run this TSR? What am I doing wrong?
>
>------ Code Deleted ------
>
Code that was here got INT 9 vector and put it in old_int. It then set
the INT 9 vector to point to new_int.
>
>new_int proc far
> jmp short go
>
>old_int dd ?
>
>go:
> jmp [old_int] ; Jump to old int routine
>new_int endp
>
>----- Code Ends ------
>
Everything looks fine except that the last jump (jmp [old_int]) has two
problems. First the jump must include a segment override so that the
data segment (ds) is not used in calculating the address of old_int.
Second you must insure that it is a far jump. Thus the line should read:
jmp far cs:[old_int]
If you still can't get it to work, email me and I will send you a sample
of how to attach to INT 9.
_______________________________________________________________________________
_ ____ _ | |
/ / / _ \ / / | Kevin T. Schmidt | schmidt@mars.jpl.nasa.gov
/ / / /_/ / / / | Jet Propulsion Laboratory | schmidt@jems.jpl.nasa.gov
_ / / / ____/ / / | 4800 Oak Grove Dr. |
/ /_/ / / / / /___ | M/S 301-355 |
\____/ /_/ /______/ | Pasadena, CA 91109 |
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!rutgers!usc!elroy.jpl.nasa.gov!jato!mars!schmidt From: schmidt@mars.jpl.nasa.gov (Kevin Schmidt) Newsgroups: comp.os.msdos.programmer Subject: Re: stealing an interrupt Message-ID: <1990Dec18.163810.21268@jato.jpl.nasa.gov> Date: 18 Dec 90 16:38:10 GMT References: <90351.150210TOMIII@MTUS5.BITNET> Sender: news@jato.jpl.nasa.gov Reply-To: schmidt@mars.UUCP (Kevin Schmidt) Organization: Jet Propulsion Laboratory, Pasadena, CA. Lines: 36 Nntp-Posting-Host: mars.jpl.nasa.gov