🚀 go-pugleaf

yogi@cs.ubc.ca (Joseph Gil) writes:

>Here is a puzzle I couldn't solve. Norton Control Center (ncc)
>and Norton Change Dir (ncd) allow one to use 35 lines on EGA
>and 40 lines on VGA. This can be easily done by downloading
>a font of 16x10 to the screen adaptor (function 11h in INT 10).
>But where is this font? It is not in the programs code (at least I couldn't
>find it there)!

>So the questions are:
>	a) Is there a 16x10 font in the ega/vga adaptor memory? Any1 has
>	a detailed manual?

No and yes.  There are 8 x 8, 8 x 14, and 8 x 16 fonts available.  And I 
think you mean 8 x 10 font.

>	b) How can this font be accessed?

It would appear that Norton supplied their own.  Unless the board is put
into graphics mode and function 1121h - int 10h is used with the 8 x 8 font.
Even then I'm not sure it can be done satisfactorily (I was able to get a 40 
line graphics mode screen but it doesn't use the entire screen -- at least
not on my machine).

>	c) Given an adapter with a font loaded in it- is there
>	a way of extracting the font from the adaptor memory?

The font information in text mode is kept in plane 2 of the display memory.
I should be possible to access it.  Further research (which I don't have 
time for) is required.

------------
;File name 40.asm

;Assemble and link as follows:

;masm 40;
;link 40;
;exe2bin 40.exe 40.com
;del 40.exe

;Generates 40 text mode on VGA screen.
;NOTE!! This is a quick and dirty test.  Checks should be made to verify this
;is a VGA card and that the functions succeed!

code    segment

        assume  cs:code

        org     100h

begin:
        mov     ax,0012h
        int     10h             ;Go into graphics mode.

        mov     ax,1130h
        mov     bh,3            ;Get the 8 x 8 font.
        int     10h             ;ES:BP has the result.

        mov     ax,1121h        ;Load alphanumeric character definitions.
        mov     cx,8            ;Bytes per char.

        mov     bl,0            ;Character rows per screen are in dl.
        mov     dl,40
        int     10h

        mov     ax,4c00h
        int     21h             ;Program terminate.

code    ends
        end        begin

-- 
joe@proto.com