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Saturday, September 28, 2019

What is CPU Registers Types of Registers (General Purpose Register) &(Special purpose Registers)

Types of Registers (General Purpose Register) & (Special purpose Registers)





Types Of Registers

Registers are categorized into two types according to their purpose and functions.

1:General  Purpose Registers
2:Special Purpose Registers

1:General  purpose Registers

General purpose register are used to Types of Registers 
store data as well as addresses.
They are combined data and address registers. 
These  registers are used for arithmetic and  data movement.
Typically these registers are 8-32 bit registers.
Following are the commonly used general purpose registers.
Types of Registers  1:Accumulator (AX)
2:Data Register (DX)
3:Base Register (BX)
4:Counter Register (CX)


1:Accumulator (AX)

Accumulator a general purpose register and is used by CPU for performing
arthmtc and logic operation and to hold  result of those operations.
The accumulator IS initially set to zero. and then each number in tum is added to
the value in the accumulator. It consists of two 8-bit registers (AH and AL)
which can be combined together and used as a one 16-bit register.

2:Base Registers (BX)

The Base Register can perform arthmtc and data movement and it has some special addressing abltes.
BX register can hold a memory address that
Points to another variable. It usually contains a data pointer.
It consists of two 8_bit registers (BH & BL) which can be combined together and used as a one 16_bit register.

3:Counter Register (CX)

The Counter Rgster acts as a counter for repting or looping instrctns. 
The Instructions given are automatically repeated and Will decrements the value Types of Registers 
of CX and quits when it is equal to 0.It consist of two 8-bit registers (CH and CL) which can combnd and used as 16_bit register CX.

3:Data Registers

Data Register has a spcl role in multiply and dvde operations.
It works like a bffer  and holds anything that copied from memory ready for Types of Registers 
the processor to use It.It also consists of two 8-bit registers (DH and DL) and can
be combined to work as a 16-bit register.In Input/Output (I/O) operations DX

register can be used as a port number. Types of Registers 

B: Special Purpose Registers

These registers hold the state of a program.They include program counter
instruction register. memory address register and memory buffer register.These are used by control unit to control the operations of CPU and by the operating system programs to control the execution of the programs.Following are the special purpose registers.

1:Instruction Register (IR)

Instruction register is a part of control unit, which stores the  Types of Registers instructions currently being executed.Each instruction tobe executed is loaded onto the instruction register.It is also known as currnt instrctn register (cir) because it holds the currnt instrction.

2:Memory Buffer Register (MAR)

Memory addrss rgister holds the memory addrss the memory addrss from which Data will be provided to the CPU or will have the address to which data will be sent and then stored. It basically hold the memory location of data that needs to be accessed.When reading form memory the data addressed by MAR is fed into the MDR (Memory Data Register) and then is used by CPU. Types of Registers  When writing to memory the CPU writes data from data register to the memory  location whose address of the memory location where the data is to be read or stored.

3:Memory Buffer Register (MBR)

The memory buffer register actually hold the content of the memory which are to be moved from memory to other components of from components to the memory. Types of Registers 
In order to store a word it must be transferred to the MBR and then from here it will go to the specific memory location.it works as a buffer allowing the processor and memory units to act independently.

4: Program Counter (PC)

Program Counter is also knwn a instrction pointer.it is a register in a computer prcessd that contain the address location of the instruction being executed at the current time. As each instrction gts fetched. The prgram counter incrse its stored value by 1.After each instrction is ftchd.The program counter points to the next instruction on the sequence.
Types of Registers .


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