type
  TMemoryAlign = (ma16Bytes, ma32Bytes, ma64Bytes, ma128Bytes, ma256Bytes,
    ma512Bytes, ma1024Bytes, ma2048Bytes);
  PMemoryAlign = ^TMemoryAlign;

  MemoryBlock = type Pointer;
  PMemoryBlock = ^MemoryBlock;

  TMemoryBlockSize = (BLOCK_4K, BLOCK_16K, BLOCK_64K, BLOCK_256K,
    BLOCK_1MB, BLOCK_4MB, BLOCK_16MB, BLOCK_64MB, BLOCK_256MB);
  PMemoryBlockSize = ^TMemoryBlockSize;

  MemoryPages = type Pointer;
  PMemoryPages = ^MemoryPages;

  TMemoryAccessRight = (marRead, marWrite, marExecute);
  PMemoryAccessRight = ^TMemoryAccessRight;
  TMemoryAccessRights = set of TMemoryAccessRight;
  PMemoryAccessRights = ^TMemoryAccessRights;

  // additional memory functions
  procedure GetMemAligned(var P: Pointer; Align: TMemoryAlign; Size: NativeInt);
  procedure RegetMem(var P: Pointer; NewSize: NativeInt);

  // block routine
  procedure GetMemoryBlock(var Block: MemoryBlock; BlockSize: TMemoryBlockSize);
  procedure FreeMemoryBlock(Block: MemoryBlock);

  // 4kb-pages routine
  procedure GetMemoryPages(var Pages: MemoryPages; Count: NativeInt);
  procedure RegetMemoryPages(var Pages: MemoryPages; NewCount: NativeInt);
  procedure ReallocMemoryPages(var Pages: MemoryPages; NewCount: NativeInt);
  procedure FreeMemoryPages(Pages: MemoryPages);

  // any 4kb-aligned memory
  procedure ChangeMemoryAccessRights(Pages: MemoryPages; Count: NativeInt; Rights: TMemoryAccessRights);

  // fast SSE-based 16-aligned memory move
  procedure MoveB16Aligned(const Source; var Dest; const B16Count: NativeInt);

type
{ TJITHeap class }
{ Just-In-Time memory heap: READ | WRITE | EXECUTE }

  IJITHeap = interface
    procedure Clear;
    function GetMemory(Size: NativeInt): Pointer;
    procedure FreeMemory(P: Pointer);
    function SyncGetMemory(Size: NativeInt): Pointer;
    procedure SyncFreeMemory(P: Pointer);
  end;

  TJITHeap = class(TInterfacedObject, IJITHeap)
  public
    constructor Create;
    destructor Destroy; override;    
    procedure Clear;

    // memory management
    function GetMemory(Size: NativeInt): Pointer;
    procedure FreeMemory(P: Pointer);

    // synchronization (spin lock) + memory management
    function SyncGetMemory(Size: NativeInt): Pointer;
    procedure SyncFreeMemory(P: Pointer);
  end;