From: Shawn Hargreaves Newsgroups: comp.os.msdos.djgpp Subject: Re: lword moves to/from video buffer fail Date: Thu, 27 Mar 1997 19:18:34 +0000 Organization: None Distribution: world Message-ID: <+SxszLAKgsOzEwDH@talula.demon.co.uk> References: <333A6B34 DOT 2C26 AT rug DOT ac DOT be> NNTP-Posting-Host: talula.demon.co.uk MIME-Version: 1.0 Lines: 22 To: djgpp AT delorie DOT com DJ-Gateway: from newsgroup comp.os.msdos.djgpp Vik Heyndrickx writes: >My question is whether lword (double word) memory access instructions >can/should be used to address video memory. In my case, this produces >problems: sometimes data isn't written at all, sometimes it ends up at >the wrong place in video memory. Usually, I don't have any problems with >my video card at all. A very interesting question. Allegro makes extensive usage of 32 bit moves to video memory (they are a _lot_ faster than 16 bit operations!) and I've never had any trouble with them, or should I say that nobody has ever complained about pixels going missing. I presume you are talking about text modes, from your comments about Rhide: do similar things happen in graphics resolutions as well? If so, does it make any difference whether you are in VGA 13h, mode-X, or an SVGA resolution? And most importantly, what type of graphics card do you have? I would be very interested in knowing more about this... -- Shawn Hargreaves - shawn AT talula DOT demon DOT co DOT uk - http://www.talula.demon.co.uk/ Beauty is a French phonetic corruption of a short cloth neck ornament.