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~: 8051 Instruction Set :~
Here one can find complete instruction set of 8051 micro-controller. Complete information regarding each instruction like operational explanation, addressing mode, no. of byte occupied, no. of cycles used etc is given. So just, go through it. It’s a ready reference.
All 8051 instructions are broadly classify in to four groups data moving, logical, arithmetic and branching.
Data moving / handling Instructions: -
|
Mnemonics |
Operational description |
Addressing mode |
No. of bytes occupied |
No. of cycles used |
|
Mov a,#num |
Copy the immediate data num in to acc |
immediate |
2 |
1 |
|
Mov Rx,a |
Copy the data from acc to Rx |
register |
1 |
1 |
|
Mov a,Rx |
Copy the data from Rx to acc |
register |
1 |
1 |
|
Mov Rx,#num |
Copy the immediate data num in to Rx |
immediate |
2 |
1 |
|
Mov a,add |
Copy the data from direct address add to acc |
direct |
2 |
1 |
|
Mov add,a |
Copy the data from acc to direct address add |
direct |
2 |
1 |
|
Mov add,#num |
Copy the immediate data num in to direct address |
direct |
3 |
2 |
|
Mov add1,add2 |
Copy the data from add2 to add1 |
direct |
3 |
2 |
|
Mov Rx,add |
Copy the data from direct address add to Rx |
direct |
2 |
2 |
|
Mov add,Rx |
Copy the data from Rx to direct address add |
direct |
2 |
2 |
|
Mov @Rp,a |
Copy the data in acc to address in Rp |
Indirect |
1 |
1 |
|
Mov a,@Rp |
Copy the data that is at address in Rp to acc |
Indirect |
1 |
1 |
|
Mov add,@Rp |
Copy the data that is at address in Rp to add |
Indirect |
2 |
2 |
|
Mov @Rp,add |
Copy the data in add to address in Rp |
Indirect |
2 |
2 |
|
Mov @Rp,#num |
Copy the immediate byte num to the address in Rp |
Indirect |
2 |
1 |
|
Movx a,@Rp |
Copy the content of external add in Rp to acc |
Indirect |
1 |
2 |
|
Movx a,@DPTR |
Copy the content of external add in DPTR to acc |
Indirect |
1 |
2 |
|
Movx @Rp,a |
Copy the content of acc to the external add in Rp |
Indirect |
1 |
2 |
|
Movx @DPTR,a |
Copy the content of acc to the external add in DPTR |
Indirect |
1 |
2 |
|
Movc a,@a+DPTR |
The address is formed by adding acc and DPTR and its content is copied to acc |
indirect |
1 |
2 |
|
Movc a, @a+PC |
The address is formed by adding acc and PC and its content is copied to acc |
indirect |
1 |
2 |
|
Push add |
Increment SP and copy the data from source add to internal RAM address contained in SP |
Direct |
2 |
2 |
|
Pop add |
copy the data from internal RAM address contained in SP to destination add and decrement SP |
direct |
2 |
2 |
|
Xch a, Rx |
Exchange the data between acc and Rx |
Register |
1 |
1 |
|
Xch a, add |
Exchange the data between acc and given add |
Direct |
2 |
1 |
|
Xch a,@Rp |
Exchange the data between acc and address in Rp |
Indirect |
1 |
1 |
|
Xchd a, @Rp |
Exchange only lower nibble of acc and address in Rp |
indirect |
1 |
1 |
Logical Instructions: -
|
Mnemonics |
Operational description |
Addressing mode |
No. of bytes occupied |
No. of cycles used |
|
Anl a, #num |
AND each bit of acc with same bit of immediate num, stores result in acc |
Immediate |
2 |
1 |
|
Anl a, add |
AND each bit of acc with same bit of content in add, stores result in acc |
Direct |
2 |
1 |
|
Anl a, Rx |
AND each bit of acc with same bit of content of Rx, stores result in acc |
Register |
1 |
1 |
|
Anl a, @Rp |
AND each bit of acc with same bit of content of add given by Rp, stores result in acc |
Indirect |
1 |
1 |
|
Anl add, a |
AND each bit of acc with same bit of direct add num, stores result in add |
Direct |
2 |
1 |
|
Anl add, #num |
AND each bit of direct add with same bit of immediate num, stores result in add |
direct |
3 |
2 |
|
orl a, #num |
OR each bit of acc with same bit of immediate num, stores result in acc |
Immediate |
2 |
1 |
|
orl a, add |
OR each bit of acc with same bit of content in add, stores result in acc |
Direct |
2 |
1 |
|
orl a, Rx |
OR each bit of acc with same bit of content of Rx, stores result in acc |
Register |
1 |
1 |
|
orl a, @Rp |
OR each bit of acc with same bit of content of add given by Rp, stores result in acc |
Indirect |
1 |
1 |
|
orl add, a |
OR each bit of acc with same bit of direct add num, stores result in add |
Direct |
2 |
1 |
|
orl add, #num |
OR each bit of direct add with same bit of immediate num, stores result in add |
direct |
3 |
2 |
|
Xrl a, #num |
XOR each bit of acc with same bit of immediate num, stores result in acc |
Immediate |
2 |
1 |
|
Xrl a, add |
XOR each bit of acc with same bit of content in add, stores result in acc |
Direct |
2 |
1 |
|
Xrl a, Rx |
XOR each bit of acc with same bit of content of Rx, stores result in acc |
Register |
1 |
1 |
|
Xrl a, @Rp |
XOR each bit of acc with same bit of content of add given by Rp, stores result in acc |
Indirect |
1 |
1 |
|
Xrl add, a |
XOR each bit of acc with same bit of direct add num, stores result in add |
Direct |
2 |
1 |
|
Xrl add, #num |
XOR each bit of direct add with same bit of immediate num, stores result in add |
direct |
3 |
2 |
|
Clr a |
Clear each bit of acc |
Direct |
1 |
1 |
|
Cpl a |
Complement each bit of acc |
direct |
1 |
1 |
|
Anl c, b |
AND carry with given bit b, stores result in carry |
-- |
2 |
2 |
|
Anl c, /b |
AND carry with complement of given bit b, stores result in carry |
-- |
2 |
2 |
|
Orl c, b |
OR carry with given bit b, stores result in carry |
-- |
2 |
2 |
|
Orl c, /b |
OR carry with complement of given bit b, stores result in carry |
-- |
2 |
2 |
|
Cpl c |
Complement carry flag |
-- |
1 |
1 |
|
Cpl b |
Complement bit b |
-- |
2 |
1 |
|
Clr c |
Clear carry flag |
-- |
1 |
1 |
|
Clr b |
Clear given bit b |
-- |
2 |
1 |
|
Mov c, b |
Copy bit b to carry |
-- |
2 |
1 |
|
Mov b, c |
Copy carry to bit b |
-- |
2 |
2 |
|
Setb c |
Set carry flag |
-- |
1 |
1 |
|
Setb b |
Set bit b |
-- |
2 |
1 |
|
Rl a |
Rotate acc one bit left |
-- |
1 |
1 |
|
Rr a |
Rotate acc one bit right |
-- |
1 |
1 |
|
Rlc a |
Rotate acc one bit left with carry |
-- |
1 |
1 |
|
Rrc a |
Rotate acc one bit right with carry |
-- |
1 |
1 |
|
Swap a |
Exchange upper and lower nibble of acc |
-- |
1 |
1 |
Arithmetic Instructions: -
|
Mnemonics |
Operational description |
Addressing mode |
No. of bytes occupied |
No. of cycles used |
|
Inc a |
Add 1 to acc |
Register |
1 |
1 |
|
Inc Rr |
Add 1 to register Rr |
Register |
1 |
1 |
|
Inc add |
Add 1 to the content of add |
Direct |
2 |
1 |
|
Inc @rp |
Add 1 to the content of the address in Rp |
indirect |
1 |
1 |
|
Inc DPTR |
Add 1 to DPTR |
Register |
1 |
2 |
|
dec a |
Subtract 1 from acc |
Register |
1 |
1 |
|
dec Rr |
Subtract 1 from Rr |
Register |
1 |
1 |
|
dec add |
Subtract 1 from content of add |
Direct |
2 |
1 |
|
dec @rp |
Subtract 1 from the content of address |
indirect |
1 |
1 |
|
Add a, #num |
Add the immediate num with acc and stores result in acc |
immediate |
2 |
1 |
|
Add a, Rx |
Add the data in Rx with acc and stores result in acc |
Register |
1 |
1 |
|
Add a, add |
Add the data in add with acc and stores result in acc |
Direct |
2 |
1 |
|
Add a, @Rp |
Add the data at the address in Rp with acc and stores result in acc
|
Indirect |
1 |
1 |
|
Addc a,#num |
Add the immediate num with acc and carry, stores result in acc |
immediate |
2 |
1 |
|
Addc a, Rx |
Add the data in Rx with acc and carry, stores result in acc |
Register |
1 |
1 |
|
Addc a, add |
Add the data in add with acc and carry, stores result in acc |
Direct |
2 |
1 |
|
Addc a, @Rp |
Add the data at the address in Rp with acc and carry, stores result in acc |
Indirect |
1 |
1 |
|
Subb a, #num |
Subtract immediate num and carry from acc; stores the result in acc |
immediate |
2 |
1 |
|
Subb a, add |
Subtract the content of add and carry from acc; stores the result in acc |
Register |
1 |
1 |
|
Subb a, Rx |
Subtract the data in Rx and carry from acc; stores the result in acc |
Direct |
2 |
1 |
|
Subb a, @Rp |
Subtract the data at the address in Rp and carry from acc; stores the result in acc |
Indirect |
1 |
1 |
|
Mul ab |
Multiply acc and register B. store the lower byte of result in acc and higher byte in B |
--- |
1 |
4 |
|
div ab |
divide acc by register B. store quotient in acc and remainder in B |
--- |
1 |
4 |
|
Da a |
After addition of two packed BCD numbers, adjust the sum to decimal format |
--- |
1 |
1 |
Branching Instructions: -
|
Mnemonic |
Operational description |
No of bytes occupied |
No. of cycles used |
|
Jc label |
Jump to label if carry is set to 1 |
2 |
2 |
|
Jnc label |
Jump to label if carry is cleared to 0 |
2 |
2 |
|
Jb b,label |
Jump to label if given bit is set to 1 |
3 |
2 |
|
Jnb b,label |
Jump to label if given bit is cleared to 0 |
3 |
2 |
|
Jbc b,label |
Jump to label if given bit is set. Clear the bit |
3 |
2 |
|
Cjne a, add, label |
Compare the content of accumulator with the content of given address and if not equal jump to label
|
3 |
2 |
|
Cjne a, #num, label |
Compare the content of accumulator with immediate number and if not equal jump to label |
3 |
2 |
|
Cjne Rx, #num, label |
Compare the content of Rx with the immediate number and if not equal jump to label |
3 |
2 |
|
Cjne @Rp, #num, label |
Compare the content of location in Rp with immediate number and if not equal jump to label |
3 |
2 |
|
Djnz Rx, label |
Decrement the content of Rx and jump to the label if it is not zero |
2 |
2 |
|
Djnz add, label |
Decrement the content of address and jump to the label if it is not zero |
3 |
2 |
|
Jz label |
Jump to the label if content of accumulator is 0 |
2 |
2 |
|
Jnz label |
Jump to the label if content of accumulator is not 0 |
2 |
2 |
|
Jmp @a+dptr |
Jump to the address created by adding the contents on accumulator and dptr |
1 |
2 |
|
Ajmp sadd |
Take a jump to absolute short range address sadd |
2 |
2 |
|
Ljmp ladd |
Take a jump to absolute long range address sadd |
3 |
2 |
|
Sjmp radd |
Take a jump to relative address radd |
2 |
2 |
|
nop |
Short form of no operation means do nothing and go to next instruction |
1 |
1 |
|
Acall sadd |
Pushes the content of Acc on stack and load it will absolute short range address sadd |
2 |
2 |
|
Lcall ladd |
Pushes the content of Acc on stack and load it will absolute long range address sadd |
3 |
2 |
|
Ret |
returns from subroutine by restoring the Acc from stack using pop operation |
1 |
2 |
|
reti |
Returns from interrupt subroutine by restoring Acc from stack using pop operation |
1 |
2 | |
