Segment registers are basically
memory pointers located inside the CPU
. Segment registers point to a place in memory where one of the following things begin: Data storage. Code execution.
What is the role of segment register?
A segment register
changes the memory address accessed by 16 bits at a time
, because its value is shifted left by 4 bits (or multiplied by 16) to cover the entire 20-bit address space. The segment register value is added to the addressing register’s 16-bit value to produce the actual 20-bit memory address.
What are the six segment registers?
The segment registers
CS, DS, SS, ES, FS, and GS
are used to identify these six current segments. Each of these registers specifies a particular kind of segment, as characterized by the associated mnemonics (“code,” “data,” or “stack”) shown in Figure 2-6 .
Which of the following is the segment register?
Explanation: The segment descriptor register is used to store the
descriptor information like attributes, limit and base
addresses of segments. Sanfoundry Global Education & Learning Series – Microprocessors.
What are segment register and its types?
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 the name of the 4 segment register?
The 8086 has four special segment registers:
cs, ds, es, and ss
. These stand for Code Seg- ment, Data Segment, Extra Segment, and Stack Segment, respectively. These registers are all 16 bits wide. They deal with selecting blocks (segments) of main memory.
What is the purpose of IP register?
A special-purpose register, usually called the instruction pointer (IP) or program counter (PC),
keeps track of what instruction is being executed.
What are the three aspects of segments in memory?
- Data segment − It is represented by . data section and the . bss. The . …
- Code segment − It is represented by . text section. This defines an area in memory that stores the instruction codes. …
- Stack − This segment contains data values passed to functions and procedures within the program.
What is memory segmentation and its advantages?
Advantages of memory segmentation:
Segmentation provides a powerful memory management mechanism
. It allows programmers to partition their programs into modules that operate independently of one another. Segments allow two processes to easily share data.
What is the difference between segment register and general purpose register?
Segments are specific areas clear in a program for containing data, code and stack. There are 3 main segments − Code Segment − It contains all the instructions to be executed. A 16-bit Code Segment register or CS register supplies the starting address of the code segment.
Are segment registers still used?
Every process access its own memory (4GB) in linear fashion, so basically the segment registers are not needed.
They are still registers
, so they can of course be used for various other assembly operations.
What are the types of registers?
- MAR Register. The full form of MAR is the memory address register. …
- MDR. The full form of MDR register is a memory data register. …
- MBR. The full form of MBR is the memory buffer register. …
- PC. The full form of PC is the program counter register. …
- Accumulator. …
- Index Register. …
- Instruction Register.
Why extra segment is used?
The es (Extra Segment) register is an extra segment register. 8086 programs often use this segment register
to gain access to segments when it is difficult or impossible to modify the other segment registers
. The ss (Stack Segment) register points at the segment containing the 8086 stack.
What is the ESP register?
The ESP register is
the stack pointer for the system stack
. It is rarely changed directly by a program but is changed when data is pushed onto the stack or popped from the stack. One use for the stack is in procedure calls. the address of the instructions following the procedure call instruction is stored on the stack.
What are registers used for?
Registers are small amounts of high-speed memory contained within the CPU. They are used by the processor
to store small amounts of data that are needed during processing
, such as: the address of the next instruction to be executed.
Where are the segment registers located?
Segment registers are basically memory pointers located
inside the CPU
.
