meillo@0: global loader           ; making entry point visible to linker
meillo@0: extern kmain             ; main is defined elsewhere
meillo@0: 
meillo@0: ; setting up the Multiboot header - see GRUB docs for details
meillo@0: MODULEALIGN equ  1<<0                   ; align loaded modules on page
meillo@0: ; boundaries
meillo@0: MEMINFO     equ  1<<1                   ; provide memory map
meillo@0: FLAGS       equ  MODULEALIGN | MEMINFO  ; this is the Multiboot 'flag' field
meillo@0: MAGIC       equ    0x1BADB002           ; 'magic number' lets bootloader find the header
meillo@0: CHECKSUM    equ  -(MAGIC + FLAGS)       ; checksum required
meillo@0: 
meillo@0: section .multiboot
meillo@0: align 4
meillo@0: MultiBootHeader:
meillo@0:    dd MAGIC
meillo@0:    dd FLAGS
meillo@0:    dd CHECKSUM
meillo@0: 
meillo@0: ; reserve initial kernel stack space
meillo@0: STACKSIZE equ 0x4000                  ; that's 16k.
meillo@0: 
meillo@0: loader:
meillo@0:    mov esp, stack+STACKSIZE           ; set up the stack
meillo@0:    push eax                           ; pass Multiboot magic number
meillo@0:    push ebx                           ; pass Multiboot info structure
meillo@0:    call kmain                          ; call kernel proper
meillo@0:    cli
meillo@0: hang:
meillo@0:    hlt                                ; halt machine should kernel return
meillo@0:    jmp   hang
meillo@0: 
meillo@0: section .bss
meillo@0: align 32
meillo@0: stack:
meillo@0:    resb STACKSIZE                     ; reserve stack on a quadword boundary