Skip to content
Related Articles

Related Articles

Auxiliary Carry Flag in 8086 Microprocessor
  • Last Updated : 05 Mar, 2021

Auxiliary Carry Flag (AF) is one of the six status flags in the 8086 microprocessor. 

  • This flag is used in BCD (Binary-coded Decimal) operations.
  • The status of this flag is updated for every arithmetic or logical operation performed by ALU.
  • This flag is set to one if there is a CARRY from the lower nibble or BORROW for the lower nibble in binary representation.
  • Else it is set to zero.

Note : Auxiliary Carry Flag is to set to one when there is a carry from the units place in hexadecimal representation. Same as the lower nibble in binary representation.

Example :

In the below image, you can see a carry takes place from the units digit. Hence auxiliary carry flag is set to one here. Here ‘H’ represents a hexadecimal number.

Auxiliary Carry Flag in Hexadecimal Representation

Let us consider the same example in binary representation. 

   29H =  0010 1001

+4CH =  0100 1100

   75H =  0111 0101

                    ^ here there is carry generated and forwarded to next nibble, so the auxiliary carry flag is set to one.

Attention reader! Don’t stop learning now. Get hold of all the important CS Theory concepts for SDE interviews with the CS Theory Course at a student-friendly price and become industry ready.

My Personal Notes arrow_drop_up
Recommended Articles
Page :