delorie.com/archives/browse.cgi   search  
Mail Archives: djgpp/1994/03/13/11:59:37

Date: Sun, 13 Mar 94 11:27:23 -0500
From: dj AT ctron DOT com (DJ Delorie)
To: FIXER AT FAXCSL DOT DCRT DOT NIH DOT GOV
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: Re: SUMMARY - Text screen I/O

> IMHO it's unfortunate that you can't write directly to the ScreenPrimary[]
> array under DMPI; that makes it impossible to use high-quality double-
> buffering schemes to update only a region of the window at any one time.
> For text graphics it's not so major an issue as it is for VGA/SVGA, but
> it's still ... inelegant.  :-)  I do consider this a bug in go32, but
> not a major one.  If it gets fixed in a later release, I'll be very
> pleased, though.

It's not a bug in go32.  It's because of two conflicting designs:

(1) DPMI 0.9 (the popular choice) doesn't support virtual mapping.
(2) gcc doesn't support far pointers.

Because of this, there is no clean way in C of directly referencing
DOS memory, no matter how smart go32 is.

DJ


- Raw text -


  webmaster     delorie software   privacy  
  Copyright © 2019   by DJ Delorie     Updated Jul 2019