Re: [Etherboot-developers] mknbi-1.2-7rc2 released

[<ke...@us...>]

>Just doing a code review I can say that there are some serious logic bugs.
>Usually there are at least 2 ram segments in the returned e820 information
>which is a little screwy.

Can you elaborate?

>But more interesting the following logic in first32.c is just wrong.
>
>		top_of_mem = ((setup->su_version >= 0x203) ?
>			setup->ramdisk_max :
>			(e->addr + e->size)
>			) >> 10;
>
>setup->ramdisk_max is in bytes not kilobytes.
>
>And if you set the top_of_ram to just under 1GB on a 16M machine your
>ramdisk will fail miserably.  Unless there is some magic that just
>makes this code work...

But top_of_mem is measured in kB (I know, it's confusing, maybe I should
rationalise that). Note the parentheses. ramdisk_max is at the same
level as e->addr + e->size. If expanded it looks like this:

	if (su_version >= 0x203)
		temp = ramdisk_max;
	else
		temp = e->addr + e->size;
	top_of_mem = temp >> 10;