{       VGA Mode Set Functions:

        Set the current video mode to mode 13h or mode 3 (text)
        WITHOUT the BIOS call!

        I learned some of this from an assembly file that I couldn't
        assemble (wouldn't work in TASM or NASM).
        I am recoding it for NASM right now, but popped it out with
        Turbo Pascal just to see if it'd work.  It did.

        Feel free to use this code, but beware:  It doesn't like
        Windows '95 a whole lot unless the DOS window is already
        full screen.

        This is good for demos/games that use their own file system and
        boot code, when by the time that the graphics function is called,
        you are already in protected mode and don't wanna switch back just
        to call a stupid 16bit real mode BIOS routine.

        If you can expand it to other modes (ModeX) or even SVGA, PLEASE
        drop me a line at mikaj@smurfy.tcimet.net

        Enjoy the code!
        Jeremy A. Mika
        Genetic Fantasia
}      

uses crt;
type
   VGAMode = record
     BIOSmode, BIOScols : byte;
     VidSeg:word;
     Misc,Feature:byte;
     Seq:array[0..4] of byte;
     Crtc:array[0..$18] of byte;
     Gfx:array[0..$8] of byte;
     Att:array[0..$14] of byte;
   end;
procedure setmode(mode:VGAMode);
const
   MISC = $3c2;
   SEQ = $3c4;
   CRTC = $3d4;
   GRAPHICS = $3ce;
   FEATURE = $3da;
   ATTRIB = $3c0;
   STATUS = $3da;

   VREND = $11;
   NOPROT = $7f;

   ENABLEATTRIB = $20;

   CURSORTOPDATA = 17;
   CURSORBOTTOMDATA = 18;

   BIOSMODE = $49;
   COLUMNS = $4a;

procedure outw(ad:word;x,y:byte);assembler;
asm
    mov ah,x
    mov al,y
    mov dx,ad
    out dx,ax
end;

var x:byte;
begin
     ASM
        mov dx,3dah
@1:     in al,dx
        test al,8
        jz @1
@2:     in al,dx
        test al,8
        jnz @2
     END;
  mem[$40:BIOSMODE]:=mode.BIOSmode;
  mem[$40:COLUMNS]:=mode.BIOScols;
  mem[$40:$61]:=mode.crtc[$a];
  mem[$40:$60]:=mode.crtc[$b];
  port[MISC]:=mode.misc;
  delay(0);
  port[FEATURE]:=mode.feature;
  delay(0);
  for x:=0 to 4 do begin
    outw(SEQ,mode.seq[x],x);
    delay(0);
  end;
  port[CRTC]:=$11;
  port[CRTC]:=mode.crtc[$11] and $7F;  {No protection!}

  for x:=0 to $18 do begin
    outw(CRTC,mode.crtc[x],x);
    delay(0);
  end;

  for x:=0 to $8 do begin
    outw(GRAPHICS,mode.gfx[x],x);
    delay(0);
  end;

  x:=port[$3da];
  delay(0);

  for x:=0 to $14 do begin
    port[ATTRIB]:=x;
    delay(0);
    port[ATTRIB]:=mode.att[x];
    delay(0);
  end;
  port[ATTRIB]:=$20;
  delay(0);
end;

const
   Mode13:VGAMode = (BIOSmode:$13; BIOScols:40;
                   VidSeg:$a000;
                   Misc:$63; Feature:$00;
                   Seq:($03,$01,$0f,$00,$0e);
                   Crtc:($5f,$4f,$50,$82,$54,$80,$bf,$1f,$00,$41,$00,$00,
                         $00,$00,$00,$00,$9c,$0e,$8f,$28,$40,$96,$b9,$a3,
                         $ff);
                   Gfx:($00,$00,$00,$00,$00,$50,$07,$0f,$ff);
                   Att:($00,$01,$02,$03,$04,$05,$06,$07,$08,$09,$0a,$0b,$0c,
                        $0d,$0e,$0f,
                        $41,$00,$0f,$00,$00)
                   );
   Mode03:VGAMode = (BIOSmode:$03; BIOScols:80;
                   VidSeg:$b800;
                   Misc:$67; Feature:$00;
                   Seq:($03,$00,$03,$00,$02);
                   Crtc:($5f,$4f,$50,$82,$55,$81,$bf,$1f,$00,$4f,$0e,$0f,
                         $00,$00,$00,$00,$9c,$0e,$8f,$28,$1f,$96,$b9,$a3,
                         $ff);
                   Gfx:($00,$00,$00,$00,$00,$10,$0e,$00,$ff);
                   Att:($00,$01,$02,$03,$04,$05,$06,$07,$08,$09,$0a,$0b,$0c,
                        $0d,$0e,$0f,
                        $0c,$00,$0f,$08,$00)
                   );

var x:byte;
  buf:array[1..2000] of char;
begin
  readln;
  move(mem[$b800:0],buf,2000);
  setmode(Mode13);
  for x:=0 to 255 do
  mem[$a000:x]:=2;
  repeat
  until keypressed;
  readkey;
  for x:=0 to 255 do begin
    setmode(Mode13);
    setmode(Mode03);
    move(buf,mem[$b800:0],2000);
  end;
  readln;
end.