(Mostly) entering long mode

lboot.S

@@ -37,8 +37,9 @@ _start:     cli
             call        print
             call        paging
 
-            mov         $msg_fin, %si
+            mov         $msg_long, %si
             call        print
+            call        long
 
             jmp         hang
 
@@ -231,6 +232,35 @@ _prnext:    mov         $COM1+5, %dx
 
 _prdone:    ret
 
+            // long: Enter long mode
+long:       
+            // Enable PAE
+            mov         %cr4, %eax
+            or          $0b100000, %eax
+            mov         %eax, %cr4
+
+            // Load page table
+            mov         pml4_ptr, %eax
+            mov         %eax, %cr3
+
+            // Enable long mode
+.set        IA32_EFER,  0xC0000080
+            mov         $IA32_EFER, %ecx
+            rdmsr
+            or          $0x100, %eax
+            wrmsr
+
+            // Enable protected mode + paging
+            mov         %cr0, %eax
+            or          $0x80000001, %eax
+            mov         %eax, %cr0
+
+            ret
+
+            // hang: sleep indefinitely
+hang:       hlt
+            jmp         hang
+
             // gdt: Protected mode / Unreal mode 16-bit GDT
 gdt:        // entry 0: null descriptor
             .word       0
@@ -257,10 +287,6 @@ gdt:        // entry 0: null descriptor
 gdt_ptr:    .word       gdt_size-1
             .long       gdt
 
-            // hang: sleep indefinitely
-hang:       hlt
-            jmp         hang
-
             // Messages to print
 msg_start:  .asciz      "Netboot via fernlader v1 ...\r\n"
 msg_a20:    .asciz      " * Enabling A20\r\n"
@@ -268,7 +294,7 @@ msg_unreal: .asciz      " * Unreal Mode\r\n"
 msg_getmap: .asciz      " * Memory Map\r\n"
 msg_mkheap: .asciz      " * Making Space\r\n"
 msg_paging: .asciz      " * Paging\r\n"
-msg_fin:    .asciz      "Finished.\r\n"
+msg_long:   .asciz      " * Long Mode\r\n"
 msg_aerr:   .asciz      "panic: Out of heap space.\r\n"
 
 heap_start: .long       0