RtlIsZeroMemory

INT8 __fastcall RtlIsZeroMemory(_BYTE *a1, UINT64 a2){
  INT8 result; 

  result = 0;
  while( ((unsigned __int8)a1 & 7) != 0 && a2 )
  {
    if( *a1 )
      return result;
    ++a1;
    --a2;
  }
  while( a2 >= 8 )
  {
    if( *(_QWORD *)a1 )
      return result;
    a1 += 8;
    a2 -= 8i64;
  }
  if( !a2 )
    return 1;
  while( !*a1 )
  {
    ++a1;
    if( !--a2 )
      return 1;
  }
  return result;
}

Referenced by:

RtlNormalizeSecurityDescriptor