heap

Docs/Kernel/Memory.md

@@ -45,12 +45,18 @@ inline increases block size, but makes it faster to find metadata and keeps it u
 Could have a single pointer to another record elsewhere, but increases complexity and does not provide
 major benefit.
 -Data (handle pointer points here)
--64 Ref count
--64 Ptr to first ref
--Optional - Stacked and single only
-  -64 Size (always need, cant interpolate even from slotted as may be smaller than slot)
-    -Always allocate bigger to word align (or page align for large?). Wont bother .NET, it never needs size from heap.
-    -If need actual size - could add 3 and mask lower 2 bits to round up.
+-32/64 Ptr to first ref
+using 32 below saves space on small/med objects. slightly increases access time, but access to these fields is not time critical
+-32 (64 to align on large) Ref count
+-32 (64 for large) Size (always need, cant interpolate even from slotted as may be smaller than slot)
+  -Always allocate bigger to word align (or page align for large?). Wont bother .NET, it never needs size from heap.
+  -If need align - could add 3 and mask lower 2 bits to round up.
+-Optional
+  -32/64 Size allocated - may be bigger and not needed for slotted etc.
+
+-Tiny 
+If needed can make tiny types too with only ref and ptr, no need for size. But check heap and
+see if such small ones are common. Probably not, likely only for boxing etc.
 
 -Small (Tables)
 Fixed sizes, max size one page. 

source/Cosmos.Core.Memory.Test/Cosmos.Core.Memory.Test.csproj

@@ -52,6 +52,9 @@
   </Choose>
   <ItemGroup>
     <Compile Include="Heap.cs" />
+    <Compile Include="HeapItemLarge.cs" />
+    <Compile Include="HeapItemMedium.cs" />
+    <Compile Include="HeapItemSmall.cs" />
     <Compile Include="RAT.cs" />
     <Compile Include="UnitTest1.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />

source/Cosmos.Core.Memory.Test/Heap.cs

@@ -9,23 +9,29 @@ namespace Cosmos.Core.Memory.Test {
 
   unsafe static public class Heap {
     static public void Init() {
-
     }
 
     static public void* New(Native aSize) {
       return null;
     }
 
-    static private void* NewBlock(int aSize) {
-      // size is inclusive? final sizse important when we get to vm
+    static private void* NewBlock(Native aSize) {
+      return NewBlockLarge(aSize);
+    }
 
-      // Block Status - 1 byte of 4
-      //    -Has Data
-      //    -Empty (Can be removed or merged)
-      // Next Block - Pointer to data. 0 if this is current last.
-      // Data Size - Native - Size of data, not including header.
-      // Data
-      return null;
+    static private void* NewBlockLarge(Native aSize) {
+      const Native xPrefixWordsLarge = 4;
+      const Native xPrefixSizeLarge = xPrefixWordsLarge * sizeof(Native);
+
+      Native xPages = (Native)((aSize + xPrefixSizeLarge) / RAT.PageSize);
+      var xPtr = (Native*)RAT.Alloc(RAT.PageType.HeapLarge, xPages);
+
+      xPtr[0] = xPages * RAT.PageSize - xPrefixSizeLarge; // Allocated data size
+      xPtr[1] = aSize; // Actual data size
+      xPtr[2] = 0; // Ref count
+      xPtr[3] = 0; // Ptr to first
+
+      return xPtr + xPrefixWordsLarge;
     }
   }
 }

source/Cosmos.Core.Memory.Test/HeapItemLarge.cs

@@ -0,0 +1,10 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Cosmos.Core.Memory.Test {
+  static public class HeapItemLarge {
+  }
+}

source/Cosmos.Core.Memory.Test/HeapItemMedium.cs

@@ -0,0 +1,10 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Cosmos.Core.Memory.Test {
+  static public class HeapItemMedium {
+  }
+}

source/Cosmos.Core.Memory.Test/HeapItemSmall.cs

@@ -0,0 +1,10 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Cosmos.Core.Memory.Test {
+  static public class HeapItemSmall {
+  }
+}

source/Cosmos.Core.Memory.Test/RAT.cs

@@ -9,8 +9,16 @@ namespace Cosmos.Core.Memory.Test {
   unsafe static public class RAT {
     static public class PageType {
       public const byte Empty = 0;
-      public const byte RAT = 1;
+
       // Data Types from 1, special meanings from 255 down.
+      public const byte RAT = 1;
+      public const byte HeapSmall = 2;
+      public const byte HeapMedium = 3;
+      public const byte HeapLarge = 4;
+      // Code
+      // Stack
+      // Disk Cache
+
       // Extension of previous page.
       public const byte Extension = 255;
     }
@@ -80,7 +88,7 @@ namespace Cosmos.Core.Memory.Test {
       return xResult;
     }
 
-    static private byte* Alloc(byte aType, Native aCount = 1) {
+    static public byte* Alloc(byte aType, Native aPageCount = 1) {
       Native? xPos = null;
 
       // Could combine with an external method or delegate, but will slow things down
@@ -88,11 +96,11 @@ namespace Cosmos.Core.Memory.Test {
       //
       // Alloc single blocks at bottom, larger blocks at top to help reduce fragmentation.
       Native xCount = 0;
-      if (aCount == 1) {
+      if (aPageCount == 1) {
         for (Native i = 0; i < mPageCount; i++) {
           if (mRAT[i] == PageType.Empty) {
             xCount++;
-            if (xCount == aCount) {
+            if (xCount == aPageCount) {
               xPos = i - xCount - 1;
               break;
             }
@@ -104,7 +112,7 @@ namespace Cosmos.Core.Memory.Test {
         for (Native i = mPageCount - 1; i >= 0; i--) {
           if (mRAT[i] == PageType.Empty) {
             xCount++;
-            if (xCount == aCount) {
+            if (xCount == aPageCount) {
               xPos = i;
               break;
             }

source/Cosmos.Core.Memory.Test/UnitTest1.cs

@@ -17,6 +17,7 @@ namespace Cosmos.Core.Memory.Test {
         Assert.IsTrue(xRatPages > 0);
         
         Native xFreePages = RAT.GetPageCount(RAT.PageType.Empty);
+        Assert.IsTrue(xFreePages > 0);
       }
     }
   }