Pagingggggggg! (identity mapped low 4M)

src/start32.asm

@@ -17,7 +17,7 @@ multiboot:
 	dd MULTIBOOT_CHECKSUM
 	dd multiboot	; header address
 	dd 0x100000	; load address
-	dd stack_bottom	; load end address
+	dd bss	; 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]!)
@@ -99,6 +99,39 @@ start:
 
 	add esp, 36	;Clean reserved uitoa return string from stack
 
+
+	;; Setup paging
+	;; Clear pagedir
+	cld
+	mov eax, 0x00000002	;Supervisor only, Write enabled, Not present
+	mov ecx, 1024
+	mov edi, pagedir
+	rep stosd
+
+	;; Clear pagetable1
+	mov edi, pagetable1
+	mov cx, 0
+.clearpt1loop:
+	mov eax, 0x00001000
+	mul ecx
+	or eax, 011b	;supervisor, rw, present
+	stosd
+	inc cx
+	cmp cx, 1024
+	jne .clearpt1loop
+
+	;; put table1 in dir
+	mov eax, pagetable1
+	or eax, 011b	;supervisor, rw, present
+	mov [pagedir], eax
+
+	;; Enable paging
+	mov eax, pagedir
+	mov cr3, eax
+	mov eax, cr0
+	or eax, 0x80000000
+	mov cr0, eax
+
 	jmp hang
 
 hang:
@@ -120,7 +153,14 @@ stuff:
 	.fbdimensionsmsgpfx db 10, "Framebuffer dimensions: ", 0
 	.x db "x", 0
 
-
+bss:
+align 4096
+pagedir:
+	rb 4096
+align 4096
+pagetable1:
+	rb 4096
+align 4096
 stack_bottom:
 rb 16384
 stack_top: