Path: utzoo!utgpu!attcan!uunet!yale!spolsky-joel From: spolsky-joel@CS.Yale.EDU (Joel Spolsky) Newsgroups: comp.sys.ibm.pc Subject: How to do fast video - summary Message-ID: <46013@yale-celray.yale.UUCP> Date: 19 Dec 88 01:51:04 GMT Sender: root@yale.UUCP Reply-To: spolsky-joel@CS.Yale.EDU (Joel Spolsky) Organization: Yale University Computer Science Dept, New Haven CT 06520-2158 Lines: 24 A while ago I asked what the politically correct way is to do fast (text) video. Several people were kind enough to reply. The following procedure should work for any display: -Find out the video mode as follows: set AH to 0x0F call interrupt 0x10 (Video Services) look in AL for the video mode -If the video mode is 7, screen memory starts at B000:0000 -otherwise, screen memory starts at B800:0000 -if the user wants snow suppression, wait for port 0x3DA to become odd before poking to the screen. Beware that if the video mode is 7, you could wait forever which is unaesthetic (Alt-Ctrl-Del time!). Some people suggested letting the BIOS output one character and then checking whether it shows up in B000 or B800. This seemed quite kludgy to me. +----------------+----------------------------------------------------------+ | Joel Spolsky | bitnet: spolsky@yalecs.bitnet uucp: ...!yale!spolsky | | | internet: spolsky@cs.yale.edu voicenet: 203-436-1483 | +----------------+----------------------------------------------------------+ #include