, BIOS' VGA BIOS:
0 CGA 25*40 only text 16 B&W 2000 0B800h
1 CGA 25*40 only text 16 2000 0B800h
2 CGA 25*80 only text 16 B&W 4000 0B800h
3 CGA 25*80 only text 16 4000 0B800h
4 CGA 25*40 320*200 4 16000 0B800h
5 CGA 25*40 320*200 2 B&W 8000 0B800h
6 CGA 25*80 640*200 2 16000 0B800h
7 MDA 25*80 only text 2 4000
0Dh EGA 25*40 320*200 16 32000 0A000h
0Eh EGA 25*80 640*200 16 64000 0A000h
0Fh EGA 25*80 640*350 2 28000 0A000h
10h EGA 25*80 640*350 16 112000 0A000h
11h VGA 30*80 640*480 2 38400 0A000h
12h VGA 30*80 640*480 16 153600 0A000h
13h VGA 25*40 320*200 256 64000 0A000h
BIOS
mov AH,0;POW39
mov AL,ScreenModeNumber
int 10h
. AX . BIOS , . ( 8,9,0Ch,0Dh). DOS - 3.
ROM RAM .
mov AH,11h;
;mov AL,11h; 8*14, 28 VGA
;mov AL,12h; 8*8, 50
mov AL,14h; 8*16, 25
mov BX,0;
int 10h
, , .
32- . , - . , .
32- , 16- .
;
ConvFactor dw 26214; 25.4
dw 25;
Inches dw 32768; 12.5
dw 12;
mMeters dw?;
dw?;
;
db 66h
mov AX,Inches;mov EAX,dword ptr ConvFactor
db 66h
mul ConvFactor; EDX:EAX
mov CL,16
db 66h
shr AX,CL;shr EAX,16
mov mMeters,AX;
mov mMeters+2,DX;
FAT
( 0) - . :
byte
0-2
3-10 ASCII -
11-12
13
14-15 =B
16 FAT
17-18
19-20
|
|
|
21 =xx
22-23 FAT =F
..
FAT B. B+F etc.
FAT DEBUG. FAT , , .
FAT :
12 bit FAT: xx 0FFh 0FFh
16 bit FAT: xx 0FFh 0FFh 0FFh
xx - .
, 2 . :
12-.FAT 16-. FAT
000h 0000h
002h-0FEFh 0002h-0FFEFh .
- .
0FF0h-0FF6h 0FFF0h-0FFF6h
0FF7h 0FFF7h bad
0FF8h-0FFFh 0FFF8-0FFFFh
, 25h. , ,
