[comp.sys.ibm.pc] ega43.scr

ted@imsvax.UUCP (Ted Holden) (12/14/86)

At least one poster has asked for info regarding the 43 line capability
of the EGA.  The following file, taken from the pages of byte, generates
ega43.com;  you simply run debug via redirection from the script file.


N EGA43.COM
A 100
MOV   AX,1112	;Load 8x8 font
MOV   BL,00
INT   10
SUB   AX,AX
MOV   DS,AX
PUSH  [0487]	;Save INFO byte
OR    BYTE PTR [0487],01
MOV   CX,0600	;Set cursor size
MOV   AH,01
INT   10
POP   [0487]	;Restore INFO byte
MOV   DX,03B4	;Fix up underline
MOV   AX,0714
OUT   DX,AX
INT   20

R CX
28
W
Q



Ted Holden,
IMS

vanzandt@uiucdcsp.cs.uiuc.edu (12/15/86)

	This doesn't quite make an EGA board switch to 43 lines per screen.
It appears that this just "shrinks" the display: the character font is
reduced (it is indeed the font in 43 line mode) but the screen starts to scroll
up at the old 12th (the new 25th) line. Result is a small copy of the 80x25
screen in the upper left corner...

	System Used: AT clone with Chips Technology components and a
	Paradise Systems AutoSwitch EGA board...

Lonnie VanZandt
@p.cs.uiuc.edu

krausej@uicsrd.CSRD.UIUC.EDU (12/17/86)

>	This doesn't quite make an EGA board switch to 43 lines per screen.
>It appears that this just "shrinks" the display: the character font is
>reduced (it is indeed the font in 43 line mode) but the screen starts to scroll
>up at the old 12th (the new 25th) line. Result is a small copy of the 80x25
>screen in the upper left corner...

  ...

>Lonnie VanZandt
>@p.cs.uiuc.edu


Lonnie,

	What's most likely happening is that the EGA is truly displaying
43 lines--but the software driving the screen (ANSI.SYS perhaps?) thinks there
are 25 lines.  I came across this problem when I was trying to get a 50-line
CGA display (yes, it is possible...) and discovered I had to mess with some
ROM-BIOS variables to make the BIOS routines aware of the 50-line screen.

	If you're really interested in using your EGA with 43 lines, check
out the public domain screen driver NANSI.SYS.  It claims to support
the 43-line mode (although I can't vouch for that, as I don't have an EGA).
There are other programs that do that same, such as Hersey Micro Consulting's
FANSI-CONSOLE (shareware, $75 for full registration).

	There may also be a way to tell the EGA BIOS to use 43 lines, but
I'm not aware of that.  Good luck!

		James Krause