Re: 16-bit bootloader support?

[Vladimir 'phcoder' Serbinenko <phcoder@gmail.com>]

Gabe Black wrote:
>
> So I have a real-time OS named Pharlap that has a 16-bit bootloader
> that ends up switching to 32-bit protected mode and loads the OS.  I
> think it relies on the first sector of the partition being loaded and
> execution simply started - but in real-mode.
>
Why do you need realmode? Using real mode requires grub2 to use more
code. MAybe booting with multiboot in 32-bit mode would be a better
idea? If you need to do some specific tasks before switching to 32-bit
mode speak about it - adding them to multiboot may be useful.
>Is there any way to have grub do this (legacy or grub2)?  I tried
chainloading, but I think that may be loading it in 32-bit mode.  Any
pointers on what code I would have to modify to >create that option for
grub?
chainloading loads in realmode, even the A20 bug is reenabled if
possible. But I discourage usage of it. Chainloading is as unportable as
you can get.
>
> Any help is appreciated.
>
> Thanks,
> Gabe Black | National Instruments | System Software | 512.683.8761
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-- 
Regards
Vladimir 'phcoder' Serbinenko
Personal git repository: http://repo.or.cz/w/grub2/phcoder.git