Article View: comp.os.msdos.programmer
Article #50Re: programs executing in video ram
From: Jerzy Tarasiuk
Date: Fri, 30 Oct 1992 04:03
Date: Fri, 30 Oct 1992 04:03
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>>>>> On Fri, 23 Oct 1992 21:00:56 GMT, d90pethe@odalix.ida.liu.se (Terminator) said: T> Here is a program (written in DEBUG) which loads a piece of code into video T> memory and runs it. Can anyone think of a use for such a program? T> (this one just makes pretty stripes on the screen) (a code to put program in video RAM removed) T> cs:120 rep movsb ; this self-replicating piece of code is T> mov cx,5 ; what gets run in video ram. T> Note that this program goes into an infinite loop that can only be exited T> by rebooting. What about instruction prefetching by CPU ? Some CPU's can get several bytes ahead, taking what was there before executing rep movsb. 8088 can get 6 bytes or so, but 80286 about 16 (I am not sure).
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Newsgroups: comp.os.msdos.programmer Path: arc1-ca.pugleaf.net!sparky!uunet!gatech!paladin.american.edu!news.univie.ac.at!hp4at!mcsun!sunic!fuw.edu.pl!cocos!jt From: jt@fuw.edu.pl (Jerzy Tarasiuk) Subject: Re: programs executing in video ram In-Reply-To: d90pethe@odalix.ida.liu.se's message of Fri, 23 Oct 1992 21:00:56 GMT Message-ID: <JT.92Oct30050356@fizyk1.fuw.edu.pl> Sender: news@fuw.edu.pl Nntp-Posting-Host: fizyk1 Organization: Warsaw University Physics Dept. References: <1992Oct23.210056.3272@ida.liu.se> Date: Fri, 30 Oct 1992 04:03:56 GMT Lines: 13