2006.1.7 :底层C编写的常用 用法
  /* The following macros process structure members:  to determine the       */
  /* offset of a structure member from the beginning of the structure, and   */
  /* to detemine the size of a member of a structure.                        */

  #define DEFS_OFFSET(s,m)       (DEFS_UI16)&(((s *)0)->m)
  #define DEFS_MEMBER_SIZE(s,m)  sizeof(((s *)0)->m)

  /* The following macros make it easier to specify binary numbers. For      */
  /* example, to specify a byte in binary:  DEFS_BINARY(01100001) or to   */
  /* specify a word in binary:  DEFS_BINARY_WORD(00111101,11001010)       */

  #define DEFS_BINARY_CONVERT(byte) (((byte & 0x10000000L) / 0x200000L) +  \
                                        ((byte & 0x01000000L) / 0x040000L) +  \
                                        ((byte & 0x00100000L) / 0x008000L) +  \
                                        ((byte & 0x00010000L) / 0x001000L) +  \
                                        ((byte & 0x00001000L) / 0x000200L) +  \
                                        ((byte & 0x00000100L) / 0x000040L) +  \
                                        ((byte & 0x00000010L) / 0x000008L) +  \
                                        ((byte & 0x00000001L) / 0x000001L))

  #define DEFS_BINARY(byte) DEFS_BINARY_CONVERT(0x##byte)

  #define DEFS_BINARY_WORD(high,low) (DEFS_BINARY_CONVERT(0x##high) * 256) + \

2006.1.7 字节交换顺序

/* This is a set of routines for demonstrating the effects of
 byte ordering between little endian and big endian machines

 Big Endian (B_ENDIAN == TRUE):

  MSB [ n | n+1 | n+2 | n+3 ] LSB

 Little Endian (B_ENDIAN == FALSE):

  MSB [ n+3 | n+2 | n+1 | n] LSB

 little/big-endian is bitness as well.  For example,

  struct {
   short b:5,   --- we _want_ signed for the example ---
   c:11;
  };

 is stored in little-endian (gint32el) ['+' denotes sign bit]:

 tf_Bitstream view -->
   0123456789A BCDEF
  |-----c----+|--b-+|

 Whereas bigendian (Motorola) stores it thus:

 tf_Bitstream view -->
   FEDCB A9876543210
  |+-b--|+----c-----|

 So, you have to invert bits as well to convert endianness.

 #define Gettf_Bit(Val,Idx) ( ( (Val) & (1<<(Idx)) ) )
 #define Settf_Bit(Val,Idx,tf_Bit) ( ( (Val) & (~(1<<Idx)) ) | ((tf_Bit)<<(Idx)) )
 for ( i = 0; i < sizeof(Val)*8; i++)
    NewVal = Settf_Bit(NewVal,sizeof(Val)*8-i-1, Gettf_Bit(Val,i));
*/        

DNP
DnpMasterStart
  --> taskSpawn ("tDnpMaster", priority, VX_FP_TASK, 0x8000,
        (FUNCPTR) DnpMasterTask,
        (int) ini_name, 0, 0, 0, 0, 0, 0, 0, 0, 0)
       
   dnpMasterTask ---> dnp_init()
                 ---> ca_task_initialize()
                 ---> ca_add_fd_registration()
                 ---> 从配置文件中得到dnp的配置信息
                 ---> pdpdvrs_initDNP()
                 ---> addr_init()
                 ---> dnp_loop()
       
  DnpMasterAddDevice
  DnpMasterAdd8550
  DnpMasterAddText
 
  DNP PEER TO PEER
 
  一些debug信息
 
  物理层
   .利用查表法来确定链路层的长度
  --->. pdpphys_initPhysRecMgr 物理层初始化,分配内存
     . valid_address()
    . pdpphys_parseDNPframe() 
 
 
  DnpMasterTask
  

========================================================

  串口:从温旧梦

   非重叠模式优点 .直接
           .易移植
        缺点 .线程中读、写相互堵塞
           .线程间相互堵塞(包括读之间,写之间,读写之间)
 
        单片机,嵌入式如vxworks,任务中相对简单的程序中常用
 
   重叠模式 优点 .灵活,效率高(后台执行操作)
           .多线程间,线程中,读写操作不会相互堵塞
        缺点 .不那么直接
           .不易于移植
   
  EV_RXCHAR:事件通知模式用在非重叠模是一个比较好的方式,因为程序不用轮询串口,以节省CPU的thread quantum
        方式如下:
       DWORD dwCommEvent;
   DWORD dwRead;
   char  chRead;
   
   if (!SetCommMask(hComm, EV_RXCHAR))
      // Error setting communications event mask.
   
   for ( ; ; ) {
      if (WaitCommEvent(hComm, &dwCommEvent, NULL)) {
         if (ReadFile(hComm, &chRead, 1, &dwRead, NULL))
            // A byte has been read; process it.
         else
            // An error occurred in the ReadFile call.
            break;
      }
      else
         // Error in WaitCommEvent.
         break;
   }
   问题出现在:当多个字节连续的发送,第1个byte到,引起EV_RXCHAR 事件发生,
                          WaitCommEvent指示可读.第2个byte紧接着到,EV_RXCHAR只是在内部置位,
                          当第1个byte读完,调用WaitCommEvent时,系统再次指示EV_RXCHAR 事件发生,
                          可读第2个byte,问题出现在当第2个字符到达,而没有被读出时,第3个字符到
                          达了,此时系统也期望将对应于第3个字符的EV_RXCHAR置位,但是系统中的
                          EV_RXCHAR标志位已经被第2个已经置位了,于是就被忽略,当第2个自负读出
        后,只能在系统缓冲区,等待第4个字符到,而读出第3个字符,这样代码和系统
                          就失去同步。
         (我觉得这种情况在一般情况下不会出现,在单片机、
                               嵌入式应该是一个一个字符往外蹦,)
   
         而且WaitCommEvent会导致很多其它事件丢失,在高速情况下。
          
    解决办法是:利用ClearCommError判断缓冲中的字符个数,一次性读完所有到达字符