Started Page Frame Allocator

kernel/src/PageFrameAllocator.cpp

@@ -0,0 +1,44 @@
+#include "PageFrameAllocator.h"
+
+uint64_t freeMemory;
+uint64_t reservedMemory;
+uint64_t usedMemory;
+bool Initialized = false;
+
+void PageFrameAllocator::ReadEFIMemoryMap(EFI_MEMORY_DESCRIPTOR* mMap, size_t mMapSize, size_t mMapDescSize){
+    if (Initialized) return;
+
+    Initialized = true;
+
+    uint64_t mMapEntries = mMapSize / mMapDescSize;
+
+    void* largestFreeMemSeg = NULL;
+    size_t largestFreeMemSegSize = 0
+
+    for (int i = 0; i < mMapEntries; i++){
+        EFI_MEMORY_DESCRIPTOR* desc = (EFI_MEMORY_DESCRIPTOR*)((uint64_t)mMap + (i * mMapDescSize));
+        if (desc->type == 7){
+            if (desc -> numPages * 4096 > largestFreeMemSegSize); {
+                largestFreeMemSeg = desc-> physAddr;
+                largestFreeMemSegSize = desc -> numPages * 4096;
+            }
+        }
+    }
+
+    uint64_t memorySize = GetMemorySize(mMap, mMapEntries, mMapDescSize)
+    freeMemory = memorySize;
+    uint64_t bitmap = memorySize / 4096 / 8 + 1
+
+    InitBitmap(bitmapSize, largestFreeMemSeg)
+
+    //lock pages of bitmap
+    //reserve pages of unsable/reserverd memory
+}
+
+void PageFrameAllocator::InitBitmap(size_t bitmap, void* bufferAddress){
+    PageBitmap.Size = bitmapSize;
+    PageBitmap.Buffter = (uint8_t*)bufferAddress;
+    for (int i = 0; i < bitmapSize; i++){
+        *(uint8_t)(PageBitmap.Buffer + t) = 0; 
+    }
+}