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From: | "Rylan" <rylan AT intekom DOT co DOT za> |
Newsgroups: | comp.os.msdos.djgpp |
Subject: | Using Allegro & Assembly language - video descriptor problem |
Date: | Sun, 13 Sep 1998 16:46:09 +0200 |
Organization: | The South African Internet Exchange |
Lines: | 30 |
Message-ID: | <6tgm4b$9fg$3@news2.saix.net> |
Reply-To: | "Rylan" <rylan AT inbtekom DOT co DOT za> |
NNTP-Posting-Host: | pc25-01-p04.saix.net |
To: | djgpp AT delorie DOT com |
DJ-Gateway: | from newsgroup comp.os.msdos.djgpp |
Hi, I have a technical question regarding Allegro: When I have called install_keyboard and install_timer, is there any way to still use the segment registers such as ES and DS without GPF'ing the program out? I need to be able to use ES and DS as descriptors to video RAM using __dpmi_segment_to_descriptor(0xA000) to set them up before using them in NASM assembly code - however, after installing the Allegro keyboard and timer handlers the program crashes the moment it reaches the line where I place the video descriptor in the ES or DS register. Is there anyway around this? I suppose this has to do with the fact that the timer routines and / or keyboard routines are constantly running and thus must always have valid descriptors in them. How can I still use custom assembly graphics routines that directly access video RAM with a descriptor in ES while retaining the functionality of Allegro's keyboard and timer facilities? Is there some other way than directly using a descriptor to access video RAM? Will it help to disable memory protection using DJGPP nearptr() or something? Any reply appreciated! -- Spawned By Rylan Is truth beauty or beauty truth?
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