如果是汇编，就按照楼上所说的用bset指令
如果是C，可以参照CW中Wizard生成的结构
typedef union {
byte Byte;
struct {
byte PTA0 :1; /* Port A Data Bit 0, Keyboard Input */
byte PTA1 :1; /* Port A Data Bit 1, Keyboard Input */
byte PTA2 :1; /* Port A Data Bit 2, Keyboard Input */
byte PTA3 :1; /* Port A Data Bit 3, Keyboard Input */
byte PTA4 :1; /* Port A Data Bit 4, Keyboard Input */
byte PTA5 :1; /* Port A Data Bit 5, Keyboard Input */
byte PTA6 :1; /* Port A Data Bit 6, Keyboard Input */
byte PTA7 :1; /* Port A Data Bit 7, Keyboard Input */
} Bits;
struct {
byte PTA :8;
} MergedBits;
} PTASTR;
extern volatile PTASTR _PTA @0x00000000;
#define PTA _PTA.Byte
#define PTA_PTA0 _PTA.Bits.PTA0
#define PTA_PTA1 _PTA.Bits.PTA1
#define PTA_PTA2 _PTA.Bits.PTA2
#define PTA_PTA3 _PTA.Bits.PTA3
#define PTA_PTA4 _PTA.Bits.PTA4
#define PTA_PTA5 _PTA.Bits.PTA5
#define PTA_PTA6 _PTA.Bits.PTA6
#define PTA_PTA7 _PTA.Bits.PTA7
#define PTA_PTA _PTA.MergedBits.PTA |
