Problem loading to al

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marek

Joined: 21 Mar 2008
Posts: 5

marek 25 Mar 2008, 13:22

Hello, I have problems with the following code (especially the line highlighted in red). The code assembles, but does not show anything.
If I do "mov al, 72", I can see yellow 'H' on the screen, so I cannot understand why the below code doesn't work.

; display string
mov ax, 0xb800
mov es, ax
xor di,di
; 0xb800:0000 - address of the first char on the screen

mov ah, 14 ; yellow

repeat strlen
mov al, byte [mystring+%-1]
stosw
end repeat

hlt

mystring db 'Hello world !!!'
strlen=$-mystring[/size]

Thanks,
Marek.

25 Mar 2008, 13:22

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 19252
Location: In your JS exploiting you and your system

revolution 25 Mar 2008, 13:28

Try using a CS override

Code:

 mov al, byte [cs:mystring+%-1]

or set DS

Code:

mov ax,cs
mov ds,ax

25 Mar 2008, 13:28

marek

Joined: 21 Mar 2008
Posts: 5

marek 25 Mar 2008, 13:56

Revolution, you are wonderful !!!

Thank you for your incredibly quick and very helpful answers !!!

Marek.

25 Mar 2008, 13:56

revolution
When all else fails, read the source

Joined: 24 Aug 2004
Posts: 19252
Location: In your JS exploiting you and your system

revolution 25 Mar 2008, 14:34

Glad to be of service.

25 Mar 2008, 14:34

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