Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site phs.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxt!mhuxv!mhuxh!mhuxi!mhuxm!mhuxj!houxm!vax135!cornell!uw-beaver!tektronix!decvax!mcnc!duke!phs!lisa From: lisa@phs.UUCP (Jeff Gillette) Newsgroups: net.micro.pc Subject: Custom Interrupt 10h ??? Message-ID: <994@phs.UUCP> Date: Tue, 5-Feb-85 23:05:06 EST Article-I.D.: phs.994 Posted: Tue Feb 5 23:05:06 1985 Date-Received: Sat, 9-Feb-85 08:08:34 EST Organization: Duke Physiology Lines: 23 <> I have a Hercules graphics card in my XT, which allows me to use a number of special fonts and foreign alphabets (which I have written) by bit-mapping the screen of the PC. All of this works very well in my applications programs, but ... I would like to substitute my own video interrupt (10h), which would allow me to use special fonts and alphabets with any [commercial] application making standard DOS calls. I have imitated the inputs/outputs for interrupt 10h calls in the PC technical manual, and the scheme works well when I set the 8088's registers and execute an interrupt 10h from an application program, but ... The operating system crashes when it tries to output a character to the screen through my custom interrupt. Is anyone aware of some special quirk of MS-DOS 2.1 that depends on a special variable or an undocumented value returned in a register? I think I am following all the specifications of the PC technical manual, but ... Jeffrey William Gillette ...!duke!phs!lisa The Divinity School Duke University