转自：http://hi.baidu.com/%B0%EB%CA%C0%CC%F4%D5%BD/blog/item/1984633dd855d53071cf6c64.html
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Symbol | Description | Byte Address |
| P0 | Port 0 | 80h |
| SP | Stack pointer | 81h |
| DPL | Data pointer (low byte) | 82h |
| DPH | Data pointer (high byte) | 83h |
| TCON | Counter/Timer control | 88h |
| TMOD | Counter/Timer operation mode | 89h |
| TL0 | Counter/Timer 0 (low byte) | 8Ah |
| TL1 | Counter/Timer 1 (low byte) | 8Bh |
| TH0 | Counter/Timer 0 (high byte) | 8Ch |
| TH1 | Counter/Timer 1 (high byte) | 8Dh |
| P1 | Port 1 | 90h |
| SCON | Serial port control | 98h |
| SBUF | Serial port buffer | 99h |
| P2 | Port 2 | 0A0h |
| IE | Interrupt Enable | 0A8h |
| P3 | Port 3 | 0B0h |
| PSW | Program Status Word | 0D0h |
| ACC | Accumulator | 0E0h |
| B | Multiplication Register | 0F0h |
BIT Symbols
| Symbol | Description | Bit Position | Bit Address |
| CY | Carry Flag | PSW.7 | 0D7h |
| AC | Auxiliary Carry Flag | PSW.6 | 0D6h |
| F0 | Flag 0 | PSW.5 | 0D5h |
| RS1 | Register Bank Select, Bit 1 | PSW.4 | 0D4h |
| RS0 | Register Bank Select, Bit 0 | PSW.3 | 0D3h |
| OV | Overflow Bit | PSW.2 | 0D2h |
| P | Parity Bit | PSW.0 | 0D0h |
| TF1 | Timer-1 Overflow Bit | TCON.7 | 8Fh |
| TR1 | Timer-1 RUN Control Bit | TCON.6 | 8Eh |
| TF0 | Timer-0 Overflow Bit | TCON.5 | 8Dh |
| TR0 | Timer-0 RUN Control Bit | TCON.4 | 8Ch |
| IE1 | Interrupt 1 Edge Flag | TCON.3 | 8Bh |
| IT1 | Interrupt 1 Control Bit | TCON.2 | 8Ah |
| IE0 | Interrupt 0 Edge Flag | TCON.1 | 89h |
| IT0 | Interrupt 0 Control Bit | TCON.0 | 88h |
| SM0 | Serial Mode Control Bit 0 | SCON.7 | 9Fh |
| SM1 | Serial Mode Control Bit 1 | SCON.6 | 9Eh |
| SM2 | Serial Mode Control Bit 2 | SCON.5 | 9Dh |
| REN | Receiver Enable Bit | SCON.4 | 9Ch |
| TB8 | Transmit Bit 8 (9-Bit Mode) | SCON.3 | 9Bh |
| RB8 | Receive Bit 8 (9-Bit Mode) | SCON.2 | 9Ah |
| TI | Transmitter Interrupt Flag | SCON.1 | 99h |
| RI | Receiver Interrupt Flag | SCON.0 | 98h |
| EA | Enable all Interrupts | IE.7 | 0AFh |
| ES | Enable serial Port Interrupt | IE.4 | 0ACh |
| ET1 | Enable Timer 1 Interrupt | IE.3 | 0ABh |
| EX1 | Enable External Interrupt 1 | IE.2 | 0AAh |
| ET0 | Enable Timer 0 Interrupt | IE.1 | 0A9h |
| EX0 | Enable External Interrupt 0 | IE.0 | 0A8h |
| RD | Read Data for External Memory | P3.7 | 0B7h |
| WR | Write Data for External Memory | P3.6 | 0B6h |
| T1 | Timer/Counter 1 Input/Output | P3.5 | 0B5h |
| T0 | Timer/Counter 0 Input/Output | P3.4 | 0B4h |
| INT1 | Interrupt 1 Input Pin | P3.3 | 0B3h |
| INT0 | Interrupt 0 Input Pin | P3.2 | 0B2h |
| TXD | Serial Port Transmit Pin | P3.1 | 0B1h |
| RXD | Serial Port Receive Pin | P3.0 | 0B0h |
| PS | Serial Port Interrupt Priority | IP.4 | 0BCh |
| PT1 | Timer 1 Interrupt Priority | IP.3 | 0BBh |
| PX1 | External Interrupt 1 Priority | IP.2 | 0BAh |
| PT0 | Timer 0 Interrupt Priority | IP.1 | 0B9h |
| PX0 | External Interrupt 0 Priority | IP.0 | 0B8h ? ? |