Re: Question on bootloader Relocation?

From: Dean Ramsier (ramsiernospam_at_nospam.com)
Date: 01/17/05 

Date: Mon, 17 Jan 2005 09:09:22 -0500

No. The bootloader must copy itself to RAM and jump there. That happens
very early, as soon as RAM is available. The code from the reset vector to
the point of relocation must be position independent.

Also note that many/most bootloaders use virtual addresses in their bib
files. So the same problem exists there. Code has to be relative until the
MMU is turned on. 

-- 
Dean Ramsier - eMVP
"Ajaya Babu" <AjayaBabu@discussions.microsoft.com> wrote in message
news:AC7858A7-8D94-4969-803C-F4705876252E@microsoft.com...
> Hi All,
>
> I am newbie to Windows CE I was going through bootloader documentation and
> code.
>
> I understand from BIB file documentation and Bootloader documentation we
can
> locate the boot loader to the RAMIMAGE + RAMOFFSET. I've seen most of the
> existing ARM bootloaders ( S3C2410, OMAP ) configure RAMIMAGE to the SDRAM
> address or Internal RAM address and relocate themselves to SDRAM from
StartUp
> routine after initialization of SDRAM controller.
>
> However StartUp routine suppose to run from RESET vector, most of the time
> from Flash located at 0 location ( in case of ARM ). But we are
configuring
> RAMIMAGE in the BIB file as SDRAM address that implicitly menas if we need
to
> run the binary from Flash  it must be position independent code is this
> correct??
>
> But who is telling Linker/Locator about this. BIB files are typically
> configuring RAMIMAGE to RAM. Does this mean entire boot loader code is
> position independent??
>
>
> -- 
> Imagination is Better than Knowledge by E=mc^2

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