fix: change the pte to use a bitmask operation (still crashes but later)

headers/memory.h

@@ -8,6 +8,7 @@
 #define ACCESSED   (1 << 4)
 #define INIT_FLAGS (PRESENT | RW | SUPERVISOR)
 #define PAGE_SIZE  4096
+#define PAGE_MASK  0xFFFFF000
 #define HEAP_END   0xC0000000
 
 void init_memory(void);