typedef struct _WHEA_ERROR_STATUS
{
     ULONG Reserved1: 8;
     ULONG ErrorType: 8;
     ULONG Address: 1;
     ULONG Control: 1;
     ULONG Data: 1;
     ULONG Responder: 1;
     ULONG Requester: 1;
     ULONG FirstError: 1;
     ULONG Overflow: 1;
     ULONG Reserved2: 41;
} WHEA_ERROR_STATUS, *PWHEA_ERROR_STATUS;

Windows Vista Kernel Structures