What are segment registers & their uses?

The segment registers stores the starting addresses of a segment. To get the exact location of data or instruction within a segment, an offset value (or displacement) is required.

What are the registers in 8086?

The registers inside the 8086 are all 16 bits. They are split up into four categories: General Purpose, Index, Status & Control, and Segment. The four general purpose registers are the AX, BX, CX, and DX registers. AX – accumulator, and preferred for most operations.

What is the use of stack segment register?

The stack segment register (SS) is usually used to store information about the memory segment that stores the call stack of currently executed program. SP points to current stack top. By default, the stack grows downward in memory, so newer values are placed at lower memory addresses.

What is the purpose of CS register?

The CS(code segment register) is used to address the code segment of the memory i.e a location in the memory where the code is stored. The IP(Instruction pointer) contains the offset within the code segment of the memory.

What is a segment register in 8086 mention each one of them?

Data segment register (DS): points to the data segment of the memory where the data is stored. Extra Segment Register (ES): also refers to a segment in the memory which is another data segment in the memory. Stack Segment Register (SS): is used for addressing stack segment of the memory.

What are registers and types of registers?

Following is the list of some of the most common registers used in a basic computer:

Register	Symbol	Function
Address register	AR	Holds address for the memory
Accumulator	AC	Processor register
Instruction register	IR	Holds instruction code
Program counter	PC	Holds address of the instruction

What is the use of base registers and offset registers?

The base address register is a pointer to a byte in memory, and the offset specifies a number of bytes. Immediate means the address is calculated using the base address register and a 12-bit offset encoded in the instruction.

What is the use of direction flag?

The direction flag is a CPU flag specific to all Intel x86-compatible CPUs. It applies to all assembly instructions that use the REP (repeat) prefix, such as MOVS, MOVSD, MOVSW, and others. Addresses provided to applicable instructions are increased if the direction flag is cleared.

What are the segment registers of 8086 microprocessor?

Segment Registers of 8086 Microprocessor are located in the Bus Interface Unit of the microprocessor. Another important unit is Execution unit where General purpose registers are located. Data Segment, Code Segment, Extra Segment and Stack Segment.

How many general purpose registers are there in 8086?

The general purpose registers are used to store temporary data in the time of different operations in microprocessor. 8086 has eight general purpose registers. This is the accumulator. It is 16-bit registers, but it is divided into two 8-bit registers. These registers are AH and AL.

How many address lines are there in 8086 microprocessor?

The number of address lines in 8086 is 20, 8086 BIU will send 20bit address, so as to access one of the 1MB memory locations. The four segment registers actually contain the upper 16 bits of the starting addresses of the four memory segments of 64 KB each with which the 8086 is working at that instant of time.

What is the difference between extra segment register and stack segment register?

Extra Segment Register (ES): also refers to a segment in the memory which is another data segment in the memory. Stack Segment Register (SS): is used for addressing stack segment of the memory. The stack segment is that segment of memory which is used to store stack data.