[OpenBIOS] Hello World
Pascal Dornier
pdornier at pcengines.com
Wed Mar 11 11:48:30 CET 1998
>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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