DOSBox now emulates several different graphics cards, and 2-3 VGA cards. Please try changing the machine-type in the DOSBox configuration and see if it helps.

(works with external video BIOS - see ldgfxrom)

@MinMax
If you read my posting carefully, you can read that I tried already all available -machine values.

@h-a-l-9000
I'll give it a try.

Thanks

Beard

so our videocard emulation is correct, but one of the bios functions isn't ?

I'd draw this conclusion.

Wild guess: set mode resetting the scanline stuff ?

@h-a-l-9000
excuse me, but the command ldgfxrom is not available inside the DOSBox.
Please give me a hint.

@QBix
Hm. it is not easy to describe.
For me it looks like that the switching to 40x25 mode works, but the
DOSBox window is not effected by this resolution switch.

I'll write a small test program and post it here soon.

Beard

@QBix
the scanline stuff is neccessary to tell the card to use the 8x8 character set.

Beard

What if you do the 40x25 modeswitch first and then set 200 lines mode?

ldgfxrom is only availible in debug DOSBox builds and it needs a video BIOS dump file of a corresponding real hardware card.

It has nothing todo with the rouitines I showed before.

I'd just written a small test program. For my suprise it was possible to switch
to the 40x25 mode without problems.

So I included the next step.
I installed the own characterset

1void CGRAMToVGA(void)
2{
3 /*
4  *  Copy the MZ-CharacterFont (CG-RAM) into the VGA-Card
5  *
6  */
7
8 __dpmi_regs Register;
9 unsigned char MZMirrorCGRAM[4096];
10 unsigned short i;
11
12 for(i = 0; i < 4096; i++) MZMirrorCGRAM[i] = Mirror(MZCGRAM[i]);
13
14
15 dosmemput(&MZMirrorCGRAM[0], 0x800, __tb);
16
17 Register.h.ah = 0x11;
18 Register.h.al = 0x10;
19 Register.h.bh = 8;     // 8 scan lines
20 Register.h.bl = 0;     // in table 0
21 Register.x.cx = 256;   // 256 characters
22 Register.x.dx = 0;     // first character is ASCII 0
23 Register.x.es = __tb >> 4;
24 Register.x.bp = __tb & 0x0F;
25 __dpmi_int(0x10, &Register);
26
27
28 dosmemput(&MZMirrorCGRAM[0x800], 0x800, __tb);
29
30 Register.h.ah = 0x11;
31 Register.h.al = 0x00;
32 Register.h.bh = 8;     // 8 scan lines
33 Register.h.bl = 1;     // in table 1
34 Register.x.cx = 256;   // 256 characters
35 Register.x.dx = 0;     // first character is ASCII 0
36 Register.x.es = __tb >> 4;
37 Register.x.bp = __tb & 0x0F;
38 __dpmi_int(0x10, &Register);
39
40
41 Register.h.ah = 0x11;
42 Register.h.al = 0x03;
43 Register.h.bl = 0x04;
44// __dpmi_int(0x10, &Register);
45
46 // Cursor off (have placed here, of course above INT's switches cursor on)
47 Register.h.ah = 0x01;
48 Register.x.cx = 0x2100;
49// __dpmi_int(0x10, &Register);
50}

And than it happens inside DOSBox.

Normally the last 2 INT10 calls are included, but for testing, I commented them out.

The link here is removed. See 2 postings below.
It is now attached.

Sourcecode and exe is included

without a parameter it uses the normal characterset,
with a parameter it downloads the MZ characterset.

Beard

I am moving this thread to DEVELOPMENT section. There is a lot of code here.

loadfont changes the scanline register as well as some others. However most of that code has been in dosbox for a long time. (the scanline stuff for 6 years).

Can't download from that site.

Hal, does vgabios or elpin work?

Hi QBix,

you are right.
I just updated the files and attached them here.

Now it is reduced to the minimum.
It happens when the user font is activated.

I had only one short fast look into the DOSBox sourcecode, so I can not say
anything about it.

It looks that the change of the scanlines has no effect to the DOSBox window.

Again:
without parameter the normal 40 by 25 mode is set.
with a parameter (DOSBoxTest xyz) the own font is activated.

Beard

Does the test app work on a real system any different than dosbox?

This is a known limitation of DOSBox regarding INT 10/AH=12/BL=30. Trying to change to 200 or 350 scanlines in VGA does not work properly, only 400 scanline text modes are supported. This was covered in another thread.

Loading a video BIOS such as the one from Bochs in a debug build of DOSBox works.

Elpin works.
What's vgabios?

@wd
On a real PC booted with FreeDOS or in a fullscreen DOS box of Win98 it works correct:
I see 320 by 200 pixels on the fullscreen and not only on half of the screen.

@ripsaw8080
That's strange, because when I make a boot disk image with FreeDOS and
run it with Bochs 2.4.1 I got the same result as with DOSBox.
Also when I use the elpin BIOS.

Beard

There aren't many games that use the alternate scanlines, but I know of a couple:

Indenture uses 200 scanlines with a custom font, but I made a workaround for it here.

Wrath of Earth uses 350 scanlines with a custom font in its installer and exit screens, but it's mostly a cosmetic issue, not really important:

Because there are few games that need the feature, I didn't think support would be added internally, so I made a TSR program that acts as an extension to DOSBox's video BIOS in order to support the alternate scanlines. An archive is attached that contains a few text mode utilities that I made, including the TSR.

SCANRES.COM is the resident program that should be loaded prior to running anything that tries to change the scanlines.

CGA.COM, EGA.COM, and VGA.COM are programs that simply switch the DOS text display to 200, 350, and 400 scanlines, respectively; and SCANRES.COM must be loaded for them to work.

CLR.COM is a program to use in place of the CLS command. DOSBox's CLS sets mode 3, so you loose the current mode and any loaded font; but this program uses the scroll window function to clear the screen, as real DOS does, and the current mode and font are preserved.

*X*.COM are a bunch of programs that set a variety of text screen dimensions, including some pretty large ones.

I've only tested the utilities with machine=svga_s3, so anything else might not work. At some point I plan to roll up all these little programs into a single program that takes a command line parameter, but I haven't gotten around to that project yet.