最近從事Embedded sysetm的工作後，常處理I/O，有需要的請自行取用 < class="code"> #define AP_FALSE 0 #define AP_TRUE 1 //======== common type define ==================== typedef unsigned char BL; typedef unsigned char U8; /* Unsigned 8 bit quantity */ typedef signed char S8; /* Signed 8 bit quantity */ typedef unsigned short U16; /* Unsigned 16 bit quantity */ typedef signed short S16; /* Signed 16 bit quantity */ typedef unsigned long U32; /* Unsigned 32 bit quantity */ typedef signed long S32; /* Signed 32 bit quantity */ /****************************************************** function name :bitclr description :清除指定位元(0) bitaddr :0~31 ******************************************************/ U32 bitclr(U32 srcvalue,U8 bitaddr) { U32 mask=1; return srcvalue&(~(mask<>bitaddr)&mask==1) return srcvalue&(~(mask<>bitaddr)&mask==bitvalue) return AP_TRUE; else return AP_FALSE; }