Feat: First try at 64-bit long jmp

boot.asm

@@ -70,7 +70,6 @@ gdt_data: ; Data Segment (0x10)
     db 10010010b ; Access Byte (0x92)
     db 11001111b ; Flags (0xC) + Limit
     db 0x0
-
 gdt_end:
 
 gdt_descriptor:
@@ -95,6 +94,38 @@ init_pm:
     mov ebp, 0x90000    ; Update stack to a safe 32-bit area
     mov esp, ebp
 
+    ; 2. Set up Paging
+    mov eax, pml4_table
+    mov cr3, eax
+
+    ; Link PML4 -> PDPT
+    mov dword [pml4_table], pdpt_table + 0x3
+    mov dword [pml4_table + 4], 0x0
+
+    ; Link PDPT -> PD
+    mov dword [pdpt_table], pd_table + 0x3
+    mov dword [pdpt_table + 4], 0x0
+
+    ; Link PD -> 2MB Physical Page 0
+    mov dword [pd_table], 0x83
+    mov dword [pd_table + 4], 0x0
+
+    ; 3. Enable PAE
+    mov eax, cr4
+    or eax, 0x20
+    mov cr4, eax
+
+    ; 4. Enable Long Mode in EFER
+    mov ecx, 0xC0000080
+    rdmsr
+    or eax, 0x00000100
+    wrmsr
+
+    ; 5. Enable Paging
+    mov eax, cr0
+    or eax, 0x80000000
+    mov cr0, eax
+
     ; 6. Print "SoraOS Protected" directly to Video Memory
     ; We can't use BIOS interrupts anymore! We must write to 0xB8000.
     mov ebx, 0xb8000
@@ -120,3 +151,23 @@ init_pm:
 times 510-($-$$) db 0
 ; The BIOS signature (must be at the very end)
 dw 0xAA55
+
+section .bss
+align 4096
+pml4_table:
+    resb 4096
+pdpt_table:
+    resb 4096
+pd_table:
+    resb 4096
+
+section .data
+gdt_ptr:
+    dw (gdt_end - gdt_start - 1)
+    dq gdt_start
+gdt_start:
+    dq 0x0000000000000000
+    dq 0x00AF9A000000FFFF ; Code
+    dq 0x00AF92000000FFFF ; Data
+gdt_end:
+