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In virtual memory implementations and memory management units, a memory map refers to page tables or hardware registers, which store the mapping between a certain process's virtual memory layout and how that space relates to physical memory addresses. In native debugger programs, a memory map refers to the mapping between loaded executable(or ...
File-backed mapping maps an area of the process's virtual memory to files; that is, reading those areas of memory causes the file to be read. It is the default mapping type. Anonymous mapping maps an area of the process's virtual memory not backed by any file, made available via the MAP_ANONYMOUS/MAP_ANON flags.
A memory-mapped file is a segment of virtual memory [1] that has been assigned a direct byte-for-byte correlation with some portion of a file or file-like resource. This resource is typically a file that is physically present on disk, but can also be a device, shared memory object, or other resource that an operating system can reference through a file descriptor.
Memory-mapped I/O is preferred in IA-32 and x86-64 based architectures because the instructions that perform port-based I/O are limited to one register: EAX, AX, and AL are the only registers that data can be moved into or out of, and either a byte-sized immediate value in the instruction or a value in register DX determines which port is the source or destination port of the transfer.
Computer memory map. C allows the programmer to control which region of memory data is to be stored. Global variables and static variables require the fewest clock cycles to store. The stack is automatically used for the standard variable declarations. Heap memory is returned to a pointer variable from the malloc() function.
To speed up context switching, some PDP-11 models provide dual R0-R5 register sets. Kernel, Supervisor (where present), and User modes have separate memory maps, and also separate stack pointers (so that a user program cannot cause the system to malfunction by storing an invalid value in the stack pointer register).
Memory-mapped I/O, an alternative to port I/O; a communication between CPU and peripheral device using the same instructions, and same bus, as between CPU and memory Virtual memory , technique which gives an application program the impression that it has contiguous working memory, while in fact it is physically fragmented and may even overflow ...
This shows the typical layout of a simple computer's program memory with the text, various data, and stack and heap sections. 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.