Anonymous user
Bootloader FAQ: Difference between revisions
→What should my bootloader support?: Make slightly less biased by saying they could be features. Also include a remark on the impossibility of a long mode higher-half kernel without paging
| [unchecked revision] | [unchecked revision] |
(→BIOS or UEFI?: Link to the section on the UEFI page) |
(→What should my bootloader support?: Make slightly less biased by saying they could be features. Also include a remark on the impossibility of a long mode higher-half kernel without paging) |
||
Line 57:
== What should my bootloader support? ==
Apart from loading the kernel, the bootloader also has to prepare the environment appropriately before handing off control to the kernel. This
* Detecting CPU/BIOS features. You need to make sure that the CPU or the BIOS supports any features that you use (e.g. INT 0x13 extensions).
* [[Detecting Memory (x86)|Getting the memory map]]. Where will you even load the kernel if you don't know what memory areas actually are memory?
* Enabling [[A20|A20]] and [[Protected Mode|protected mode]] with [[Paging|paging]] (or [[Long Mode|long mode]] if running on a [[x86-64|x86_64]]). GRUB doesn't enable paging or long mode, but that doesn't mean other bootloaders shouldn't do
** There might not be actually any memory at that address;
** It makes it a bit harder, if not impossible, and more messy to do a [[Higher Half Kernel|higher half kernel]].
When you are more advanced, you may also want/need to do these things in the bootloader:
| |||