kernel/start32.asm

format elf
use32

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_MAGIC	    equ 0x1BADB002
MULTIBOOT_HEADER_FLAGS	    equ MULTIBOOT_PAGE_ALIGN or MULTIBOOT_MEMORY_INFO or MULTIBOOT_VIDEO_REQUEST
MULTIBOOT_CHECKSUM          equ -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS)

.multiboot: align 4
	dd MULTIBOOT_HEADER_MAGIC
	dd MULTIBOOT_HEADER_FLAGS
	dd MULTIBOOT_CHECKSUM
; 	dd 0	; header address
; 	dd 0	; load address
; 	dd 0	; load end address
; 	dd 0	; bss end address
; 	dd 0	; 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

section '.bss' writable align 16
	stack_bottom:
	rb 16384
	stack_top:

section '.text' executable
	public  _start
	extrn   kmain

disable_cursor:
	pushf
	push eax
	push edx

	mov dx, 0x3D4
	mov al, 0xA	; low cursor shape register
	out dx, al

	inc dx
	mov al, 0x20	; bits 6-7 unused, bit 5 disables the cursor, bits 0-4 control the cursor shape
	out dx, al

	pop edx
	pop eax
	popf
	ret

_start:
	; Setup stack
	mov esp, stack_top

	; Call the main kernel function.
	call disable_cursor
	call kmain


@@:
	cli
	hlt
	jmp     @b