Minimum RAM requirements for coreboot (under Qemu)

[bifferos]

Coreboot seems to require a minimum of 64MB to run, but I would like to port it to a platform with only 32MB.  I noticed in:

targets/emulation/qemu-x86/qemu-x86/normal/crt0.S

there is the line:

movl	$0x4000000, %esp

which I have changed to

movl	$0x2000000, %esp

The boot now gets a lot further, but my payload (FILO) still doesn't 
appear to run.

Is there some fundamental reason why platforms with <64MB are not 
supported?

The last thing I see is:

Copying Interrupt Routing Table to 0x000f0000... done.
Copying Interrupt Routing Table to 0x03ff0000... done.
Moving GDT to 0x3ff0400...ok
Multiboot Information structure has been written.
Writing high table forward entry at 0x00000500
Wrote coreboot table at: 00000500 - 00000518  checksum f3df
New low_table_end: 0x00000500
Now going to write high coreboot table at 0x03ff0800
rom_table_end = 0x03ff0800
Adjust low_table_end from 0x00000500 to 0x00001000
Adjust rom_table_end from 0x03ff0800 to 0x04000000

So no surprise that it doesn't work, but how/where do I change 
these values?

thanks
Biff.

[Peter Stuge]

bifferos wrote:
> Is there some fundamental reason why platforms with <64MB are not
> supported?

No. Some addresses are hardcoded in places where there could be more
clever algorithms.

More clever algorithms come with the risk of error, which is nice to
avoid as far as possible in firmware, but yeah..

//Peter

[ron minnich]

On Sun, May 17, 2009 at 8:04 AM, bifferos  wrote:
> So no surprise that it doesn't work, but how/where do I change
> these values?

It's hard to get a machine with that little memory any more. I think
that's the reason for the high number.

I'll take a look today or tomorrow unless someone beats me to it.
Sorry for the inconvenience!

ron