Began rewrite

kernel/src/entry.s

@@ -1,108 +1,40 @@
-;
-; Kernel entry point
-;
-
-MBH_MAGIC	equ 0xe85250d6
-MBH_ARCH	equ 0x00000000
-STACK_SIZE	equ 4096
-global VIRT_BASE
-KERN_VIRT_BASE	equ 0xC000000
-KERN_PAGE_NUM	equ (KERN_VIRT_BASE >> 22)
-
 bits 32
 
-; Multiboot2 Header
+; Flag bits
+%define ALIGN	1<<0
+%define MEMINFO	1<<1
+
+; Field values
+%define MAGIC	0x1BADB002
+%define FLAGS	(ALIGN | MEMINFO)
+%define CHECK	-(MAGIC + FLAGS)
+
+; Multiboot 1 header
 section .multiboot
-align 64
-mbh:
-; Magic fields
-.magic: 	dd MBH_MAGIC
-.arch:		dd MBH_ARCH
-.size:		dd (mbh.end - mbh)
-.checksum:	dd 0x10000000 - (MBH_MAGIC + MBH_ARCH + (mbh.end - mbh))
+align 4
+multiboot:
+	dd MAGIC
+	dd FLAGS
+	dd CHECK
 
-; Framebuffer Tag
-align 8
-dw 5	; Type - Framebuffer
-dw 1	; Flags	- Optional
-dd 20	; Size
-dd 1920	; Width
-dd 1080	; Height
-dd 32	; Depth
-
-; Zero Tag
-align 8
-dw 0	; Type - Zero
-dw 0	; Flags
-dd 8	; Size	
-
-.end:
-
-; Stack
+; Initialize stack
 section .bss
 align 16
 stack_bottom:
-	resb 16384*8
+resb 16384	; 16kB
 stack_top:
 
-; Entry section
-section .boot
-global start
-
-extern kmain
-start:
-	; Init temporary paging
-	mov eax, (initpd - 0xC0000000)
-	mov cr3, eax
-
-	mov ecx, cr4
-	or ecx, 0x10	; Paging enable bit
-	mov cr4, ecx
-
-	mov ecx, cr0
-	or ecx, 0x8000000
-	mov cr0, ecx
-
-	jmp higher_half
-
-Shutdown:
-	mov ax, 0x1000
-	mov ss, ax
-	mov sp, 0xf000
-	mov ax, 0x5307
-	mov bx, 0x0001
-	mov cx, 0x0003
-	int 0x15
-
+; Entry point
 section .text
-higher_half:
-	mov esp, stack_top	; Stack Pointer
+global _start
+extern kmain
+_start:
+	mov esp, stack_top
 
-	add ebx, KERN_VIRT_BASE ; Make address in EBX virtual
-	push ebx		; Push multiboot mem info pointer
+	call kmain	; Call kernel main
 
-	call kmain
-
-; Halt on return
-cli
-h: 	hlt
-	jmp h
-
-section .data
-
-; Inital Page Directory
-align 4096
-global initpd
-initpd:
-	dd 0b10000011		; Initial 4MB identity map
-
-	times 768-1 dd 0	; Padding
-
-	; Higher half kernel start, map 16MB
-	dd (0 << 22) | 0b10000011
-	dd (1 << 22) | 0b10000011
-	dd (2 << 22) | 0b10000011
-	dd (3 << 22) | 0b10000011
-
-	times 256-4 dd 0	; More padding
+	; Hang if kernel returns
+	cli
+.hlt:	hlt
+	jmp .hlt