kernel/src/start32.asm

92 lines
1.6 KiB
NASM

format binary
use32
org 0x100000
MULTIBOOT_HEADER_MAGIC equ 0x1BADB002
MULTIBOOT_PAGE_ALIGN equ (1 shl 0)
MULTIBOOT_MEMORY_INFO equ (1 shl 1)
MULTIBOOT_VIDEO_REQUEST equ (0 shl 2)
MULTIBOOT_AOUT_KLUDGE equ (1 shl 16)
MULTIBOOT_HEADER_FLAGS equ MULTIBOOT_PAGE_ALIGN or MULTIBOOT_MEMORY_INFO or MULTIBOOT_VIDEO_REQUEST
MULTIBOOT_HEADER_FLAGS equ MULTIBOOT_PAGE_ALIGN or MULTIBOOT_MEMORY_INFO or MULTIBOOT_VIDEO_REQUEST or MULTIBOOT_AOUT_KLUDGE
MULTIBOOT_CHECKSUM equ -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS)
multiboot:
dd MULTIBOOT_HEADER_MAGIC
dd MULTIBOOT_HEADER_FLAGS
dd MULTIBOOT_CHECKSUM
dd multiboot ; header address
dd 0x100000 ; load address
dd stack_bottom ; load end address
dd stack_top ; bss end address
dd start ; entry address
dd 0 ; video mode_type (0:fb, 1:txt) (set flags[2]!)
dd 1024 ; video width
dd 768 ; video height
dd 32 ; video depth
start:
; Setup stack
mov ebp, stack_bottom
mov esp, stack_top
push ebx
push eax
cmp eax, 0x2badb002
jne multibootnomagic
mov byte [0xb8000], '!'
mov esi, stuff.bootmsg
call serialinit
call printbootmsg
call serialwrite
jmp hang
hang:
cli
hlt
jmp hang
multibootnomagic:
mov esi, .msg
mov edi, 0xb8000
mov ah, 64
cld
.loop:
lodsb
or al, al
jz .done
stosw
jmp .loop
.done:
jmp hang
.msg db "No multiboot magic", 0
printbootmsg:
pushad
mov edi, 0xb8000
cld
.loop:
lodsb
or al, al
jz .done
stosb
inc edi
jmp .loop
.done:
popad
ret
include "src/serial.asm"
stuff:
.bootmsg db "=== KoalemOS ===", 0
stack_bottom:
rb 16384
stack_top: