x86-64 Grub question

crazygray1 · Post by **crazygray1** » Sat Jan 12, 2008 1:56 pm

when you install grub on an ISO when running a 64 bit OS does Grub enter long mode for you? Where can I find more info on what Grub does?

bluecode · Post by **bluecode** » Sat Jan 12, 2008 2:18 pm

Grub legacy conforms to the Multiboot Specification and does not enter long mode for you. Grub2 might (read as I don't know) do this, but it is not yet stable.

crazygray1 · Post by **crazygray1** » Sat Jan 12, 2008 2:32 pm

Where does GRUB load the kernel?

Combuster · Post by **Combuster** » Sat Jan 12, 2008 5:13 pm

crazygray1 wrote:Where does GRUB load the kernel?

RTFM. Link already posted.

crazygray1 · Post by **crazygray1** » Sat Jan 12, 2008 8:40 pm

kristian@Kristian:~/Documents/Decipher/Source/Kernel$ ld linker.ld kernel.o startkernel.o
ld: i386 architecture of input file `kernel.o' is incompatible with i386:x86-64 output
ld: i386 architecture of input file `startkernel.o' is incompatible with i386:x86-64 output
kristian@Kristian:~/Documents/Decipher/Source/Kernel$ ld linker.ld kernel.o startkernel.o

what do I do to change this

piranha · Post by **piranha** » Sun Jan 13, 2008 12:14 am

To emulate i386 on 64 bit:
gcc: -m32

nasm: -f elf32

gas: --32

ld: -m elf_i386

Those are the options for the commands.
(you may have to re-compile)
-JL

crazygray1 · Post by **crazygray1** » Sun Jan 13, 2008 6:58 am

my problem was with the ld commands.
thanks

crazygray1 · Post by **crazygray1** » Sun Jan 13, 2008 2:10 pm

someone on the IRC said that when booting from a cd that your bootloader has to be 2kb is that the limit? Or is there a limit at all?

Brynet-Inc · Post by **Brynet-Inc** » Sun Jan 13, 2008 2:32 pm

I have a hard time beleving you actually carefully read that Wiki page...

Look carefully at the "External links" section... there is a "related" document there.

crazygray1 · Post by **crazygray1** » Sun Jan 13, 2008 2:40 pm

I have that doc saved on my computer.