[Etherboot-developers] Relocation successs...

[Eric W B. <ebi...@ln...>]

I am probably certifiable at this point but I have a working
relocatable etherboot.  Including the framework for 16bit
calls.  But the 16bit code isn't done.

The fun part is putting etherboot in an endless loop booting itself :)

What I have for 16bit code, is a 16bit that you pass a stack below
1M and it will pop all of it's arguments of the registers, and the
address of the function to jmp to off of the stack.  Leaving just
a prepopulated return address, and whatever arguments came with
the stack.

I aimed at a single general purpose function because I felt that
writing multiple stub functions, and handling everything else would
start getting quite complicated, and push the amount of memory
we need below 1MB.

Currently below 1MB I need about 400 bytes + 1k or so for a stack.

I'm a little frustrated because it feels like whenever I try something
to make the code smaller the size actually grows a little.  Everything
except the decompressor code anyway :)  The practical growth is only
a couple of hundred bytes...

With respect to decompressor code.  There should be enough space in
the low 640K to hold both the compressed, and the uncompressed
etherboot so I don't need an inplace decompressor.  I plan on placing
the decompressor at 0x10000 and etherboot at something like 0x24000,
when using relocation.

Relocating polling drivers isn't to much of a hassle.  It is just
a matter of placing calls to virt_to_bus in all of the appropriate
places.  For the few drivers we have that used memory mapped io
devices we will need calls to ioremap as well.  And sorting
that out will be a little interesting.

I'm to tired to safely commit anything tonight, but sometime in the
next couple of days, I will commit my work to date.

Eric