Mercurial > selfmade-os
comparison loader.s @ 0:99db6262c157
initial commit with code from http://wiki.osdev.org/Bare_bones
| author | meillo@marmaro.de |
|---|---|
| date | Sun, 01 Nov 2009 23:50:00 +0100 |
| parents | |
| children |
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| -1:000000000000 | 0:99db6262c157 |
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| 1 global loader ; making entry point visible to linker | |
| 2 extern kmain ; main is defined elsewhere | |
| 3 | |
| 4 ; setting up the Multiboot header - see GRUB docs for details | |
| 5 MODULEALIGN equ 1<<0 ; align loaded modules on page | |
| 6 ; boundaries | |
| 7 MEMINFO equ 1<<1 ; provide memory map | |
| 8 FLAGS equ MODULEALIGN | MEMINFO ; this is the Multiboot 'flag' field | |
| 9 MAGIC equ 0x1BADB002 ; 'magic number' lets bootloader find the header | |
| 10 CHECKSUM equ -(MAGIC + FLAGS) ; checksum required | |
| 11 | |
| 12 section .multiboot | |
| 13 align 4 | |
| 14 MultiBootHeader: | |
| 15 dd MAGIC | |
| 16 dd FLAGS | |
| 17 dd CHECKSUM | |
| 18 | |
| 19 ; reserve initial kernel stack space | |
| 20 STACKSIZE equ 0x4000 ; that's 16k. | |
| 21 | |
| 22 loader: | |
| 23 mov esp, stack+STACKSIZE ; set up the stack | |
| 24 push eax ; pass Multiboot magic number | |
| 25 push ebx ; pass Multiboot info structure | |
| 26 call kmain ; call kernel proper | |
| 27 cli | |
| 28 hang: | |
| 29 hlt ; halt machine should kernel return | |
| 30 jmp hang | |
| 31 | |
| 32 section .bss | |
| 33 align 32 | |
| 34 stack: | |
| 35 resb STACKSIZE ; reserve stack on a quadword boundary |