最新天堂中文在线丨午夜嘿嘿嘿影院丨亚洲国产精品高清久久久丨中文字幕人成乱码熟女app丨www91亚洲丨97成人资源丨成人中文字幕+乱码+中文字幕丨一区二区三区在线 | 日丨日韩免费大片丨亚洲欧美一区二区三区丨国产在线观看a丨亚洲成人第一区丨国内免费视频成人精品丨亚洲综合色网站丨午夜精品美女久久久久av福利丨国产午夜人做人免费视频网站丨国产又黄视频丨97se狼狼狼狼狼亚洲网丨狠狠亚洲婷婷综合色香五月丨中国一级毛片黄丨国产女人十八毛片丨国产色视频在线播放丨国产亚洲精久久久久久无码苍井空丨天天摸日日摸爽爽狠狠丨久久综合香蕉国产蜜臀av

西門子S7-300 BCC數(shù)據(jù)效驗(yàn)和             誰(shuí)有用過(guò)的程序？分享一份。謝謝

接口： IN: DB_NO  INT  DB number
           LEN    INT  Length of source area
       OUT:RETVAL INT  RETVAL
       TEMP:w_db_no  Word  DB number
            w_bcc_value  Word   actual BCC value
            w_temp_val   Word   temporary value
            d_loop_akt   DWord  actual value of the loop counter
            d_loop       DWord  loop counter

  L     #LEN                        // load length                  
      L     2                           // decrement length by 2
      -I                                // last 2 bytes are reserved for BCC
      SLD   3                           // calculate bit offset
      T     #d_loop                     // save the last bit address

      L     #DB_NO                      // load DB number
      T     #w_db_no
      OPN   DB [#w_db_no]               // and open DBs

      L     0
      T     #d_loop_akt                 // initialize loop counter
      T     #w_bcc_value                // initialize the BCC

// loop for calculating the BCC for (LEN - 2) bytes
// abort if d_loop_akt = d_loop

LOOP: L     DBB [#d_loop_akt]           // load byte from DB
      L     #w_bcc_value                // load actual BCC
      XOW                               // EXOR
      T     #w_bcc_value                // and save

      L     8                           // increment the bit address by 8
      L     #d_loop_akt                 // to address the next byte
      +D    
      T     #d_loop_akt

      L     #d_loop
      <I    
      JC    LOOP

// load the actual BCC
// and compare with the last two bytes of the source DB
// example: #LEN      22
//           0..19     data bytes
//           20,21     BCC-HI, BCC-LO

      L     #w_bcc_value                // load BCC
      AW    W#16#F0                     //separate the most significant nibble
      SLW   4                           // shift the least significant nibble to the highbyte
      OW    W#16#3000                   // OR 30h to Highbyte to receive ASCII character
      T     #w_temp_val                 // and save temporary

      L     #w_bcc_value                // load BCC
      AW    W#16#F                      //separate the least significant nibble
      OW    W#16#30                     // OR 30h to Lowbyte to receive ASCII character
      L     #w_temp_val
      OW    

      L     DBW [#d_loop_akt]           // Load BCC from DB
      ==I                               // and compare
      L     0                           // value of RETVAL, if comparison ok
      JC    ENDE

      L     -1                          // value of RETVAL, if comparison not ok
ENDE: T     #RETVAL

      BE