Editing Memory address (section)

===Address space in application programming===
In modern [[computer multitasking|multitasking]] environment, an [[application program|application]] [[process (computing)|process]] usually has in its address space (or spaces) chunks of memory of following types:
* '''[[Machine code]]''', including:
** program's own code (historically known as ''[[code segment]]'' or ''text segment'');
** [[shared libraries]].
* '''[[Data (computing)|Data]]''', including:
** initialized data ([[data segment]]);
** [[.bss|uninitialized (but allocated)]] variables;
** [[run-time stack]];
** [[heap (programming)|heap]];
** [[Shared memory (interprocess communication)|shared memory]] and [[memory mapped file]]s.
Some parts of address space may be not mapped at all.

Some systems have a "split" [[memory architecture]] where machine code, constants, and data are in different locations, and may have different address sizes.
For example, [[PIC18]] microcontrollers have a 21-bit program counter to address machine code and constants in Flash memory, and 12-bit address registers to address data in SRAM.