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Data Manipulation Instructions in Computer Organization
  • Difficulty Level : Easy
  • Last Updated : 05 Jan, 2021

Data Manipulation Instructions :
Data manipulation instructions perform operations on data and provide the computational capabilities for the computer. The data manipulation instructions in a typical computer usually divided into three basic types as follows.

  1. Arithmetic instructions
  2. Logical and bit manipulation instructions
  3. Shift instructions

Let’s discuss one by one.

  1. Arithmetic instructions :
    The four basic arithmetic operations are addition, subtraction, multiplication, and division. Most computers provide instructions for all four operations.

    Typical Arithmetic Instructions –

    NameMnemonicExampleExplanation
    IncrementINCINC B

    It will increment the register B by 1  



     B<-B+1

    DecrementDECDEC B

    It will decrement the register B by 1  

    B<-B-1

    AddADDADD B

    It will add contents of register B to the contents of the  accumulator

     and store the result in the accumulator  

    AC<-AC+B

    SubtractSUBSUB B

    It will subtract the contents of register B from the contents of the 

    accumulator  and store the result in the accumulator



    AC<-AC-B

    MultiplyMULMUL B

    It will multiply the contents of register B with the contents of the 

    accumulator and store the result in the accumulator

    AC<-AC*B

    DivideDIVDIV B

    It will divide the contents of register B with the contents of the 

    accumulator and store the quotient in the accumulator

    AC<-AC/B

    Add with carry ADDCADDC B 

    It will add the contents of register B and the carry flag with the

    contents of the accumulator and store the result in the 

    accumulator

    AC<-AC+B+Carry flag

    Subtract with borrowSUBBSUBB B

    It will subtract the contents of register B and the carry flag from 

    the contents of the accumulator and store the result in the 

    accumulator

    AC<-AC-B-Carry flag

    Negate(2’s complement)NEGNEG  B

    It will negate a value by finding 2’s complement of its single operand.

    This means simply operand by -1.

    B<-B’+1

  2. Logical and Bit Manipulation Instructions :
    Logical instructions perform binary operations on strings of bits stored in registers. They are useful for manipulating individual bits or a group of bits.

    Typical Logical and Bit Manipulation Instructions –

    NameMnemonicExampleExplanation
    ClearCLRCLR 

    It will set the accumulator to 0 

    AC<-0

    ComplementCOMCOM A

    It will complement the accumulator

    AC<-(AC)’

    ANDANDAND B

    It will AND the contents of register B with the contents of accumulator and store 

    it in the accumulator

    AC<-AC AND B

    OROROR B

    It will OR the contents of register B with the contents of accumulator and store it

    in the accumulator

    AC<-AC OR B

    Exclusive-ORXORXOR B

    It will XOR the contents of register B with the contents of the accumulator and 

    store it in the accumulator

    AC<-AC XOR B

    Clear carryCLRCCLRC

    It will set the carry flag to 0

    Carry flag<-0

    Set carrySETCSETC

    It will set the carry flag to 1

    Carry flag<-1

    Complement carryCOMCCOMC

    It will complement the carry flag

    Carry flag<- (Carry flag)’

    Enable interruptEIEIIt will enable the interrupt
    Disable interruptDIDIIt will disable the interrupt
  3. Shift Instructions :
    Shifts are operations in which the bits of a word are moved to the left or right. Shift instructions may specify either logical shifts, arithmetic shifts, or rotate-type operations.

    Typical Shift Instructions –

    NameMnemonic
    Logical shift rightSHR
    Logical shift leftSHL
    Arithmetic shift rightSHRA
    Arithmetic shift leftSHLA
    Rotate rightROR
    Rotate leftROL
    Rotate right through carryRORC
    Rotate left through carryROLC

    For Shift Instructions, refer to this Reference for Shift Instructions

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