not working

kernel/memory/pageframealloc.cc

@@ -15,6 +15,10 @@ void mark_pageframes(uintptr_t start, uintptr_t end, bool available){
     DBG << "start: " << hex << start << " end: " << end;
     start = Page::floor(start);
     end = Page::ceil(end);
+    if(start > 4294967296)
+        start = 4294967296;
+    if(end > 4294967296)
+        end = 4294967296;
     DBG << " page start: " << hex << start << " end: " << end << endl;
 
     for(uint64_t i = start; i < end; i += 4096){
@@ -116,7 +120,7 @@ PageFrame* PageFrameAllocator::alloc(bool kernel){
     }
     else{
         search_start = 0x4000000;
-        search_end = 0x8000000;
+        search_end = 0x8000000; //TODO find some appropriate value
     }
 
     uint64_t free_pageframe=0;