有一段程序GetPortVal(0x281,&D8L,1);\x05GetPortVal(0x282,&D4H,1);m_data = (D4H&0x0f);\x05m_data = (m_data
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![有一段程序GetPortVal(0x281,&D8L,1);\x05GetPortVal(0x282,&D4H,1);m_data = (D4H&0x0f);\x05m_data = (m_data](/uploads/image/z/6914867-59-7.jpg?t=%E6%9C%89%E4%B8%80%E6%AE%B5%E7%A8%8B%E5%BA%8FGetPortVal%280x281%2C%26D8L%2C1%29%3B%5Cx05GetPortVal%280x282%2C%26D4H%2C1%29%3Bm_data+%3D+%28D4H%260x0f%29%3B%5Cx05m_data+%3D+%28m_data)
有一段程序GetPortVal(0x281,&D8L,1);\x05GetPortVal(0x282,&D4H,1);m_data = (D4H&0x0f);\x05m_data = (m_data
有一段程序
GetPortVal(0x281,&D8L,1);
\x05GetPortVal(0x282,&D4H,1);
m_data = (D4H&0x0f);
\x05m_data = (m_data
有一段程序GetPortVal(0x281,&D8L,1);\x05GetPortVal(0x282,&D4H,1);m_data = (D4H&0x0f);\x05m_data = (m_data
D4H&0x0f是取D4H变量中数据的低4位.
"&"作为运算符表示按位与运算."&"放在变量前面(如" &D8L")则表示取得该变量的指针(地址).(在这里并非引用的意思,表示引用应在函数声明时放在变量的后面)
GetPortVal(0x281,&D8L,1); // 从端口位置0x281处获取数据给D8L
GetPortVal(0x282,&D4H,1); // 从端口位置0x282处获取数据给D4H
m_data = (D4H&0x0f); //取D4H变量中数据的低4位赋值给m_data
m_data = (m_data