Registers In CPU - General Purpose Register & Special purpose Registers

Registers are the memory which holds data within CPU. The types of registers are mentioned below.

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

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 the arithmetic tasks and data movement and it has some special addressing tables.
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 Register acts as a counter for reporting or looping instructions
The Instructions given are automatically repeated and Will decrements the value Types of Registers CX and quits when it is equal to 0. It consists 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 special role in multiply and divide operations. Yes its a powerful register.
It works like a buffer  and holds anything that copied from memory ready for Types of Registers the processor to use It..It is so good for working. It also consists of two 8-bit registers (DH and DL) and can be combined to work as a 16-bit register.Input/Output (I/O) operations DX register can be used as a port number.

Special Purpose Registers

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





1:Instruction Register (IR)




The instruction register is a part of the control unit, which stores the current data being executed. .It is also available. Each instruction to be executed is loaded onto the instruction register. It is also known as current instruction register (cir) because it holds the current instruction.





2:Memory Buffer Register (MAR)




Memory address register holds the memory address 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. The good thing is that it is very fast and powerful. When reading from 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 is to be moved from memory to other components of from components to the memory. Power 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 known an instruction pointer.it is a register in a computer prcessd that contains 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 counterpoints to the next instruction on the sequence. You can find these registers within the CPU.




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