typedef struct _SEGMENT_FLAGS
{
     ULONG TotalNumberOfPtes4132: 10;
     ULONG ExtraSharedWowSubsections: 1;
     ULONG LargePages: 1;
     ULONG WatchProto: 1;
     ULONG DebugSymbolsLoaded: 1;
     ULONG WriteCombined: 1;
     ULONG NoCache: 1;
     ULONG FloppyMedia: 1;
     ULONG DefaultProtectionMask: 5;
     ULONG ContainsPxeSubsection: 1;
     ULONG Spare: 9;
} SEGMENT_FLAGS, *PSEGMENT_FLAGS;

Windows Vista Kernel Structures