Re: [OpenBIOS] Hello World

[Pascal Dornier]

> The MDA cards require absolutely no setup. They display text from the

moment
> the power goes on. I suspect older [CEV]GA cards will be similar.

Not correct, you need to initialize the 6845 CRTC. Pardon the grotty
formatting.

;
 ; Init Hercules card
 ;
 cld
 mov al,#$21 ;disable video
 mov dx,#$03b8
 out dx,al
 mov si,#herctext ;set text mode
 mov bl,#0
 mov dx,#$03b4
hercloop mov al,bl
 out dx,al
 inc dx
 cs: lods.b
 out dx,al
 dec dx
 inc bx
 cmp bl,#16
 jb hercloop
 mov al,#$29 ;enable video
 mov dx,#$3b8
 out dx,al
 mov ax,#$b000 ;clear screen
 mov es,ax
 mov ax,#vidfill
 mov cx,#2000
 mov di,#0
 rep stos
 jmp hercend
  ;
  ; Hercules text mode settings
  ;
herctext B $61,$50,$52,$0F,$19,$06,$19,$19  ; mode 7
 B $02,$0D,$0B,$0C,$00,$00,$00,$00
hercend

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Hello World

[span]

Hmmm
i used some code like this when i tried to write some diagnostic roms
for testing 'dead' motherboards...
most 'dead' boards where the result of memmory problems in the first 64k
of ram.. (untill thats been tested as good you cant generally init the 
vga class cards by there bios entry point).
what i did was to init an original mda card from ibm and use the bottem 
two lines of the display as memmory.
(if thay were displayed it looked good going through my diags with the
stack sitting in display memmory)
however the speed penalty for useing a 486 cpu was drastic in the extreme
it would take hours to do a reasnoble ram test.

On Wed, 11 Mar 1998, Pascal Dornier wrote:
> > The MDA cards require absolutely no setup. They display text from the
>
> moment
> > the power goes on. I suspect older [CEV]GA cards will be similar.
>
> Not correct, you need to initialize the 6845 CRTC. Pardon the grotty
> formatting.
>
> ;
>  ; Init Hercules card
>  ;
>  cld
>  mov al,#$21 ;disable video
>  mov dx,#$03b8
>  out dx,al
>  mov si,#herctext ;set text mode
>  mov bl,#0
>  mov dx,#$03b4
> hercloop mov al,bl
>  out dx,al
>  inc dx
>  cs: lods.b
>  out dx,al
>  dec dx
>  inc bx
>  cmp bl,#16
>  jb hercloop
>  mov al,#$29 ;enable video
>  mov dx,#$3b8
>  out dx,al
>  mov ax,#$b000 ;clear screen
>  mov es,ax
>  mov ax,#vidfill
>  mov cx,#2000
>  mov di,#0
>  rep stos
>  jmp hercend
>   ;
>   ; Hercules text mode settings
>   ;
> herctext B $61,$50,$52,$0F,$19,$06,$19,$19  ; mode 7
>  B $02,$0D,$0B,$0C,$00,$00,$00,$00
> hercend
>
> OpenBIOS -- http://www.linkscape.net/openbios/
> [e-mail]   Body: un/subscribe
> Problems?  [e-mail]

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