struct MMPTE_SOFTWARE

typedef struct _MMPTE_SOFTWARE
{
     ULONG Valid: 1;
     ULONG PageFileLow: 4;
     ULONG Protection: 5;
     ULONG Prototype: 1;
     ULONG Transition: 1;
     ULONG Unused: 20;
     ULONG PageFileHigh: 32;
} MMPTE_SOFTWARE, *PMMPTE_SOFTWARE;

Windows Vista Kernel Structures