Table of Contents
What is the difference between data and bss section?
What is the difference between the Data and BSS sections? BSS refers to uninitialized global and static objects and Data refers to initialized global and static objects. Both BSS and Data usually refer to RAM objects.
Where the static variables are stored in memory?
data segment
When the program (executable or library) is loaded into memory, static variables are stored in the data segment of the program’s address space (if initialized), or the BSS segment (if uninitialized), and are stored in corresponding sections of object files prior to loading.
What is BSS text?
In a nutshell: ‘text’ is your code, and constants (and also the vector table). ‘data’ is for initialized variables. The initialized value allocates space in FLASH which then is copied from ROM to RAM in the startup code. ‘bss’ is for the uninitialized data in RAM which is initialized with zero in the startup code.
Where are static variables stored in assembly?
The static variables are stored in the data segment of the memory. The data segment is a part of the virtual address space of a program. All the static variables that do not have an explicit initialization or are initialized to zero are stored in the uninitialized data segment( also known as the BSS segment).
What is the use of bss section?
bss section is used by the compiler for global and static variables. It is one of the default COFF sections that is used to reserve a specified amount of space in the memory map that can later be used for storing data. It is normally uninitialized. All global and static variables in a C program are placed in the .
What is BSS data segment?
In computer programming, the block starting symbol (abbreviated to . bss or bss) is the portion of an object file, executable, or assembly language code that contains statically allocated variables that are declared but have not been assigned a value yet. It is often referred to as the “bss section” or “bss segment”.
Are static variables stored in Heap?
Storage Area of Static Variable in Java Method area section was used to store static variables of the class, metadata of the class, etc. Whereas, non-static methods and variables were stored in the heap memory. After the java 8 version, static variables are stored in the heap memory.
Where variables are stored?
Variables are usually stored in RAM. This is either on the Heap (e.g. global variables, static variables in methods/functions) or on the Stack (e.g. non-static variables declared within a method/function). Stack and Heap are both RAM, just different locations. Pointers are a bit special.
Why is it called BSS?
Historically, BSS (from Block Started by Symbol) is a pseudo-operation in UA-SAP (United Aircraft Symbolic Assembly Program), the assembler developed in the mid-1950s for the IBM 704 by Roy Nutt, Walter Ramshaw, and others at United Aircraft Corporation.
What is static variable in C?
What is a Static Variable? In programming, a static variable is the one allocated “statically,” which means its lifetime is throughout the program run. It is declared with the ‘static’ keyword and persists its value across the function calls.
Why are BSS and data separate?
To clarify: the only difference between . data and . bss is that on start-up, the “copy-down” can be run sequentially, hence faster. If it were not split into the two segments then the initialisation would have to skip the RAM spots belonging to the uninitialised variables, so wasting time.
Where are static variables stored in the memory?
The static variables are stored in the data segment of the memory. The data segment is a part of the virtual address space of a program.
What is the difference between the data section and bss segment?
When checking the disassembly of the object file through the readelf, I see the data and the bss segments contain the same offset address. The data section will contain the initialised global and static variables.
What is the difference between uninitialized and BSS data?
Uninitialized data starts at the end of the data segment and contains all global variables and static variables that are initialized to zero or do not have explicit initialization in source code. 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 BSS section in C++?
The .bss section is guaranteed to be all zeros when the program is loaded into memory. So any global data that is uninitialized, or initialized to zero is placed in the .bss section. For example: