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Hi Ranieri,
I have think about it. I concern
about Real Mode Interrupt. Since JJOS is running under Protected
Mode.
As I know, most of the real mode interrupt will not
work under protected mode. If JJOS can provide a Real
Mode Interface, we could save lots of
times.
Regards,
Hilary
----- Original Message -----
Sent: 26 August 1999 PM 22:14
Subject: Re: [JOS-Kernel] decaf
updates
>>cool, do you read the fonts from the vid-mem? the start
routine
>>clears unforunately the hole vid-mem, so no fonts after the
stop routine
>>are available (yet).
>
>well, I just copy
the font from Linux and store in byte array. and draw it
>pixel on the
screen. I think that would be much more easy to do it.
>hm, What's
vid-mem ? :o, I remember that font are stored in VGA.
>But I
forget how to retrieve it from VGA. is there any Doc?
This is the way
to retrieve it using the BIOS. This might prove to be a bit problematic in OS
design, but solving this problem is left as an excersize for the reader
;-D
This info has been extracted from Ralf Brown's interrupt list, file
inter60a.zip available through ftpsearch.lycos.com ....
Hope it helps
someone somewhere ...
Ranieri
--------V-101130-----------------------------
INT 10 - VIDEO - GET
FONT INFORMATION (EGA, MCGA,
VGA)
AX =
1130h
BH =
pointer
specifier
00h INT 1Fh
pointer
01h INT 43h
pointer
02h ROM 8x14 character font
pointer
03h ROM 8x8 double dot font
pointer
04h ROM 8x8 double dot font (high 128
characters)
05h ROM alpha alternate (9 by 14) pointer
(EGA,VGA)
06h ROM 8x16 font (MCGA,
VGA)
07h ROM alternate 9x16 font (VGA only) (see
#00021)
11h (UltraVision v2+) 8x20 font (VGA) or 8x19 font (autosync
EGA)
12h (UltraVision v2+) 8x10 font (VGA) or 8x11 font (autosync EGA)
Return:
ES:BP = specified
pointer
CX
= bytes/character of on-screen font (not the requested
font!)
DL
= highest character row on screen
Note: for
UltraVision v2+, the 9xN alternate fonts follow the
corresponding
8xN font at ES:BP+256N
BUG: the IBM
EGA and some other EGA cards return in DL the number of rows
on
screen rather than the highest row number (which is one less).
SeeAlso:
AX=1100h,AX=1103h,AX=1120h,INT 1F"SYSTEM DATA",INT 43"VIDEO
DATA"
Format of alternate font table
[array]:
Offset Size Description (Table
00021)
00h BYTE character
to be replaced (00h = end of table)
01h N
BYTEs graphics data for character, one byte
per scan
line
--------V-101130BX4D4F-----------------------
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