What is meant by code segment?

What is meant by code segment?

In computing, a code segment, also known as a text segment or simply as text, is a portion of an object file or the corresponding section of the program’s virtual address space that contains executable instructions.

What is code segment in C++?

The code segment (also called a text segment), where the compiled program sits in memory. The code segment is typically read-only. The data segment (also called the initialized data segment), where initialized global and static variables are stored. The heap, where dynamically allocated variables are allocated from.

What is code segment in microprocessor?

Code segment (CS) is a 16-bit register containing address of 64 KB segment with processor instructions. The processor uses CS segment for all accesses to instructions referenced by instruction pointer (IP) register. CS register cannot be changed directly.

What is BSS and data segment?

The BSS segment, also known as uninitialized data, is usually adjacent to the data segment. The BSS segment contains all global variables and static variables that are initialized to zero or do not have explicit initialization in source code.

What is data segment and code segment?

The code segment, also known as text segment contains the machine instructions of the program. The code can be thought of like the text of a novel: It tells the story of what the program does. The data segment contains the static data of the program, i.e. the variables that exist throughout program execution.

What are the three aspects of segment in memory?

Memory Segments

• 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 extra segment?

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.

What are the different segments in the memory?

Basically, the memory layout of C program contains five segments these are the stack segment, heap segment, BSS (block started by symbol), DS (Data Segment) and text segment. Each segment has own read, write and executable permission.

What do you mean by memory segmentation?

Memory segmentation is an operating system memory management technique of division of a computer’s primary memory into segments or sections. Different segments may be created for different program modules, or for different classes of memory usage such as code and data segments.

What is the stack segment?

The Stack Segment is a segment that holds a stack. It’s a stack implementation of memory locations. As the stack is a segment, it is a contiguous array of memory locations.

What is the responsibility of stack segment?

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. To push a value to the stack, the PUSH instruction is used. To pop a value from the stack, the POP instruction is used.

What type of memory is used for extra segment?

The need of memory segmentation is explained below: The BIU (Bus Interfacing Unit) contains four special purpose registers called as segment registers. These are Code Segment (CS) register, Stack Segment (SS) register, Extra Segment (ES) register and Data Segment (DS) register. All these are 16 bit registers.

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 do you mean by segment register?

Filters. A register that points to the base of the current segment being addressed. See segmented address space.

Which segment register is used with Di?

extra segment register

Are segment registers still used?

The FS and GS segment registers are still used on x86-64: In 64-bit mode, segmentation is generally (but not completely) disabled, creating a flat 64-bit linear-address space. The processor treats the segment base of CS, DS, ES, SS as zero, creating a linear address that is equal to the effective address.