Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.PCS 1/10/84; site ahuta.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxj!houxm!ahuta!dmt From: dmt@ahuta.UUCP (d.tutelman) Newsgroups: net.micro.pc Subject: Re: Elementry "C" question for the PC Message-ID: <353@ahuta.UUCP> Date: Fri, 11-Jan-85 07:39:12 EST Article-I.D.: ahuta.353 Posted: Fri Jan 11 07:39:12 1985 Date-Received: Sat, 12-Jan-85 05:39:12 EST References: <1050003@acf4.UUCP> Organization: AT&T Information Systems Labs, Holmdel NJ Lines: 26 CC: dmt REFERENCES: <1050003@acf4.UUCP> The question of how to clear the screen from "C" programs is very dependent on the particular C you're using. However, a good way to do it in general is to exercise the BIOS call that sets the screen mode. Here's how. Using whatever your C uses to generate a program interrupt, call interrupt 10H, setting AH to 0 (Set Mode) and AL to whatever mode you want to be in after the ClearScreen (the mode for standard monochrome alphanumerics is 7). ALTERNATIVE: A less portable way, but maybe easier from your program, is to zero the display memory. Both the Alpha and Graphics displays are memory mapped to locations between B0000 and BFFFF hex. If you're only using one screen anyway (no background or hidden screens) and don't care about performance, zero the whole 64K. Otherwise, check the Tech Ref to see where in RAM your display is and zero it. (The latter is hardware dependent; it may not work from one manufacturer's display board to another, or from the monochrome to color board.) Happy hacking! Dave Tutelman