Re: simple message under BIOS/CSM/LEGACY

[Pascal]

between `start:` and `cli` ?

Le lun. 1 août 2022 à 09:50, SteveSi <easy2boot@gmail.com> a écrit :

> Maybe clear direction flag first?
>
> cld
>
> ??
>
>
> On Mon, 1 Aug 2022 at 08:40, Pascal <patatetom@gmail.com> wrote:
>
>> hi,
>>
>> I have a live system with only UEFI boot supported.
>>
>> to indicate this to users who have not yet switched to UEFI, I have below
>> this simple little piece of code (partly found on the internet) that I
>> compile with nasm and I push onto the MBR.
>>
>> it runs perfectly on some PCs and in virtual machine with Qemu, but
>> refuses
>> to run on other PCs by displaying either a kind of smiley logo or a simple
>> blinking cursor.
>>
>> does anyone have any idea or clue about this?
>>
>> regards, lacsaP.
>>
>> 8<--------------------------------
>> ; nasm nobioscsm.asm -f bin -o nobioscsm
>>
>> bits 16
>> org 0x7C00
>>
>> start:
>>     cli
>>     mov si, msg
>>     mov ah, 0x0E
>>     .loop lodsb
>>     or al, al
>>     jz halt
>>     int 0x10
>>     jmp .loop
>>
>> halt:
>>     hlt
>>
>> msg:
>>     db 0x0D, 0x0A, '** Boot with BIOS/CSM no longer supported : reboot
>> with
>> EFI/UEFI **', 0
>>
>> ;times 510 - ($-$$) db 0
>> ;dw 0xAA55
>>
>