;   This file is part of Fennix Kernel.
;
;   Fennix Kernel is free software: you can redistribute it and/or
;   modify it under the terms of the GNU General Public License as
;   published by the Free Software Foundation, either version 3 of
;   the License, or (at your option) any later version.
;
;   Fennix Kernel is distributed in the hope that it will be useful,
;   but WITHOUT ANY WARRANTY; without even the implied warranty of
;   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;   GNU General Public License for more details.
;
;   You should have received a copy of the GNU General Public License
;   along with Fennix Kernel. If not, see <https://www.gnu.org/licenses/>.

[bits 32]
KERNEL_STACK_SIZE equ 0x4000 ; 16KB

extern DetectCPUID
extern Detect64Bit
extern DetectPSE
extern DetectPAE
extern multiboot_main
extern LoadGDT32
extern BootPageTable

section .bootstrap.data
MB_HeaderMagic:
	dq 0

MB_HeaderInfo:
	dq 0

section .bootstrap.text

global Multiboot2_start
Multiboot2_start:
	cli

	mov [MB_HeaderMagic], eax
	mov [MB_HeaderInfo], ebx

	call DetectCPUID
	cmp eax, 0
	je $

	; call Detect64Bit
	; cmp eax, 0
	; je $

	call DetectPSE
	cmp eax, 0
	je $

	; call DetectPAE
	; cmp eax, 0
	; je $

	mov ecx, cr4
	or ecx, 0x00000010 ; Set PSE in CR4
	; or ecx, 0x00000020 ; Set PAE in CR4
	mov cr4, ecx

	call LoadGDT32

	mov ecx, BootPageTable
	mov cr3, ecx

	mov ecx, cr0
	or ecx, 0x80000001 ; Set PG and PE in CR0
	mov cr0, ecx

	mov esp, KernelStack + KERNEL_STACK_SIZE
	mov eax, [MB_HeaderMagic]
	mov ebx, [MB_HeaderInfo]
	push ebx
	push eax
	call multiboot_main
.Hang:
	hlt
	jmp .Hang

section .bootstrap.bss
align 16
KernelStack:
	resb KERNEL_STACK_SIZE