struct KSPECIAL_REGISTERS

typedef struct _KSPECIAL_REGISTERS
{
     ULONG Cr0;
     ULONG Cr2;
     ULONG Cr3;
     ULONG Cr4;
     ULONG KernelDr0;
     ULONG KernelDr1;
     ULONG KernelDr2;
     ULONG KernelDr3;
     ULONG KernelDr6;
     ULONG KernelDr7;
     DESCRIPTOR Gdtr;
     DESCRIPTOR Idtr;
     WORD Tr;
     WORD Ldtr;
     ULONG Reserved[6];
} KSPECIAL_REGISTERS, *PKSPECIAL_REGISTERS;

Windows Vista Kernel Structures