What is special purpose register in microprocessor?

A Special Function Register (or Special Purpose Register, or simply Special Register) is a register within a microprocessor, which controls or monitors various aspects of the microprocessor’s function.

What is special purpose register and its types?

A special purpose register is one that has a specific control or data handling task to carry out. There are a number of special purpose registers within the CPU. The diagram above shows that the CPU contains a number of registers in order to process data and to follow program instructions.

What are the 2 special purpose registers?

Special purpose registers ( SPR ) hold program state; they usually include the program counter (aka instruction pointer), stack pointer, and status register (aka processor status word).

Which register is a special purpose register?

a) Program counter (PC) – Program is a sequence of instructions. As mentioned earlier, microprocessor fetches these instructions from the memory and executes them The program counter is a special purpose register which, at a given time,stores the address of the next instruction to be fetched.

How many types of special purpose registers are there?

In general, a CPU uses eight general-purpose registers such as accumulator, data register, address register, source index, destination index, base pointer, stack pointer, and base register.

What is the size of special purpose registers?

SI – This is the source index register. It is of 16 bits. It is used in the pointer addressing of data and as a source in some string related operations.

Is stack pointer a special purpose register?

But in the complete programmer’s view of 8085, there are two more special purpose registers, each of 16-bit width. They are the stack pointer, SP, and the program counter, PC.

How many special purpose registers are there in 8085?

six general – purpose registers
The 8085 has six general – purpose registers to store 8-bit data; these are identified as B, C, D, E, H and L as shown in the figure. They can be combined as register pairs – BC, DE, and HL – to perform some 16-bit operations.

What is the difference between SFR and GPR?

Data memory is made up of the Special Function Registers (SFR) area, and the General Pur- pose Registers (GPR) area. The SFRs control the operation of the device, while GPRs are the general area for data storage and scratch pad operations. The data memory is banked for both the GPR and SFR areas.

What is SP register?

The Stack Pointer (SP) register is used to indicate the location of the last item put onto the stack. When you PUT something ONTO the stack (PUSH onto the stack), the SP is decremented before the item is placed on the stack.

Why accumulator is called special purpose register?

The accumulator takes a value in, operates on it and puts the value out; it could be stored in short term memory, stored in longer term memory, written to an output port or other peripheral. What comes out of the accumulator is effectively the processors reason for existence which makes it pretty special.

Which of the following are special purpose register in 8085 microprocessor?

Flag registers: The flag register is a special purpose register and it is completely different from other registers in microprocessor. It consists of 8 bits and only 5 of them are useful.

How many general purpose registers are there in 8086 microprocessor?

eight general purpose registers
The general purpose registers are used to store temporary data in the time of different operations in microprocessor. 8086 has eight general purpose registers.

What is the difference between special purpose register and general purpose register?

Special purpose registers hold the status of a program. These registers are designated for a special purpose. Some of these registers are stack pointer, program counter etc. General purpose registers hold the temporary data while performing different operations.

What is the difference between special purpose and general purpose?

A general purpose computer is used for different programs for different functions. It can be used to do a lot of things. A speical-purpose computer is designed for special functions only. It is usually made to do one thing only.

What is the size of SP register?

The stack pointer in the 8085 microprocessor is a 16-bit register that stores the address of the top of stack memory. The value of the stack pointer is decremented by 2 in the PUSH operation. It will increment by 2 in POP operation.

What is SP in assembly language?

SP (or R13) is the stack pointer. The C and C++ compilers always use SP as the stack pointer. Use of SP as a general purpose register is discouraged. In Thumb, SP is strictly defined as the stack pointer.

What is the purpose of general purpose registers?

The general-purpose registers are used to calculate data and store addresses. The control register is further classified into the PC (program counter) to control program progress and the CCR (condition code register) to test conditions.

What are the different types of register in 8086 discuss general purpose register?

8086 has four 16-bit general-purpose registers AX, BX, CX and DX. These are available to the programmer, for storing values during programs. Each of these can be divided into two 8-bit registers such as AH, AL; BH, BL; CL, CH and DL, DH. Beside their general use, these registers also have some specific functions.

What is the difference between general and special purpose registers?

There are 8 general purpose registers in 8086 microprocessor. AX – This is the accumulator. It is of 16 bits and is divided into two 8-bit registers AH and AL to also perform 8-bit instructions.

What is the flag register in microcontroller 8086?

Microprocessor Microcontroller 8086 The flag register is one of the special purpose register. The flag bits are changed to 0 or 1 depending upon the value of result after arithmetic or logical operations. 8086 has 16-bit flag register, and there are 9 valid flag bits.

What are pointers in 8086 microprocessor?

3) Pointers and Index Registers. The pointers will always store some address or memory location. In 8086 Microprocessor, they usually store the offset through which the actual address is calculated. Instruction Pointer (IP): The instruction pointer usually stores the address of the next instruction that is to be executed.

What is the use of general purpose registers in microprocessor?

General purpose registers are used to store temporary data within the microprocessor. There are 8 general purpose registers in 8086 microprocessor.