To: Steve Blinkhorn <steve AT prd DOT co DOT uk>
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu (djgpp mailinglist)
Subject: Re: fast text screen access 
Date: Wed, 21 Dec 94 08:48:05 +0200
From: "Eli Zaretskii" <eliz AT is DOT elta DOT co DOT il>

> I'm in the process of porting from BCC, and there is a just
> perceptible latency in painting the screen with menus when, using
> assembler routines and direct access to video memory, they used to
> flash up apparently instantly.

DJGPP has all the text-mode screen access functions that BCC
offers.  Do you see that latency when you use the same
functions the original BCC-compiled program used?  I did
such a port awhile ago, and found DJGPP library functions
no slower then BCC's, except in DPMI mode.  Do you run your
program in DPMI mode?  If so, and if you don't run under
Windows' DOS box, put ``nodpmi'' into your GO32 environment
variable, and you will see much faster screen writes.

Btw, does anybody on the list know why in DPMI mode screen
accesses are so much slower?