lisa@phs.UUCP (Jeff Gillette) (02/06/85)
<> 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