Working on "DOS" VGA.

[Damjan Jovanovic]

On Sat, Apr 3, 2010 at 5:34 PM, Alexandre Julliard <julliard at winehq.org> wrote:
> Stefan Dösinger <stefandoesinger at gmx.at> writes:
>
>> Am 02.04.2010 um 02:08 schrieb chris ahrendt:
>>
>>> Just my 2 phennings worth on this...
>>> Why reinvent the wheel... I would say instead of doing the emulator inside wine... or a JIT... why not have
>>> wine intersept the call to start the vm86 mode.. and forks off and starts DOSEMU or whatever DOS box system is
>>> configured.. That way wine doesnt have to worry about it...
>> Because you can mix modes in one executable. Take for example the
>> average modern dos game: They start as real mode apps, then switch to
>> a 32 bit protected mode dos extender(e.g. dos4gw.exe). I wouldn't be
>> surprised if the app can transform itself into a Win16 app that tries
>> to pop up a window. Wouldn't work well in Linux dosemu.
>
> DOS apps can't do that. Pretty much the only thing you really have to
> share is the filesystem, and it should be easy to configure DosBox to
> mount ~/.wine/drive_c, and to invoke Wine when a DOS app starts a
> Windows binary.
>
> There's no reason to replicate DosBox inside Wine. On the contrary, a
> nice project would be to improve integration with an external DOS
> emulator and then rip out the half-broken vm86 support from Wine.
>
> --
> Alexandre Julliard
> julliard at winehq.org
>
>
>

But Win16 applications can access DOS int 0x21 functions (below,
tested successfully on Wine and Vista), and at least some hardware
(http://www.faqs.org/faqs/windows/programming/vxd/ describes how a
Win16 application can access the VGA framebuffer). Doesn't that mean
we need the vm86 support in Wine?

Damjan

#include <windows.h>

int PASCAL WinMain( HINSTANCE this_inst, HINSTANCE prev_inst,
                    LPSTR cmdline, int cmdshow )
{
    int val;
    char buffer[512];
    __asm mov ax,0x6200
    __asm mov bx,0
    __asm int 0x21
    __asm mov val,bx
    sprintf(buffer, "Hi from Win16 with PSP = %d", val);
    MessageBox(NULL, buffer, "Hello world", MB_OK);
    __asm mov ax,0x4c00
    __asm int 0x21
    /*return 0;*/
}