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Stack Allocation
Stacks in computing architectures are regions of memory where data is added or removed in a last-in-first-out (LIFO) manner. In most modern computer systems, each thread has a reserved region of memory referred to as its stack. When a function executes, it may add some of its local state data to the top of the stack; when the function exits it is responsible for removing that data from the stack. At a minimum, a thread's stack is used to store the location of a return address provided by the caller in order to allow return statements to return to the correct location. The stack is often used to store variables of fixed length local to the currently active functions. Programmers may further choose to explicitly use the stack to store local data of variable length. If a region of memory lies on the thread's stack, that memory is said to have been allocated on the stack, i.e. stack-based memory allocation (SBMA). This is contrasted with a heap-based memory allocation (HBMA). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UNIX/32V
UNIX/32V is an early version of the Unix operating system from Bell Laboratories, released in June 1979. 32V was a direct port of the Seventh Edition Unix to the DEC VAX architecture. Overview Before 32V, Unix had primarily run on DEC PDP-11 computers. The Bell Labs group that developed the operating system was dissatisfied with DEC, so its members refused DEC's offer to buy a VAX when the machine was announced in 1977. They had already begun a Unix port to the Interdata 8/32 instead. DEC then approached a different Bell Labs group in Holmdel, New Jersey, which accepted the offer and started work on what was to become 32V. Performed by Tom London and John F. Reiser, porting Unix was made possible due to work done between the Sixth and Seventh Editions of the operating system to decouple it from its "native" PDP-11 environment. The 32V team first ported the C compiler (Johnson's pcc), adapting an assembler and loader written for the Interdata 8/32 version of Unix to the VAX ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stack Machine
In computer science, computer engineering and programming language implementations, a stack machine is a computer processor or a Virtual machine#Process virtual machines, process virtual machine in which the primary interaction is moving short-lived temporary values to and from a push down Stack (abstract data type), stack. In the case of a hardware processor, a hardware stack is used. The use of a stack significantly reduces the required number of processor registers. Stack machines extend push-down automata with additional load/store operations or multiple stacks and hence are Turing-complete. Design Most or all stack machine instructions assume that operands will be from the stack, and results placed in the stack. The stack easily holds more than two inputs or more than one result, so a rich set of operations can be computed. In stack machine code (sometimes called p-code), instructions will frequently have only an opcode commanding an operation, with no additional fields i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stack Buffer Overflow
In software, a stack buffer overflow or stack buffer overrun occurs when a program writes to a memory address on the program's call stack outside of the intended data structure, which is usually a fixed-length buffer. Stack buffer overflow bugs are caused when a program writes more data to a buffer located on the stack than what is actually allocated for that buffer. This almost always results in corruption of adjacent data on the stack, and in cases where the overflow was triggered by mistake, will often cause the program to crash or operate incorrectly. Stack buffer overflow is a type of the more general programming malfunction known as buffer overflow (or buffer overrun). Overfilling a buffer on the stack is more likely to derail program execution than overfilling a buffer on the heap because the stack contains the return addresses for all active function calls. A stack buffer overflow can be caused deliberately as part of an attack known as . If the affected program is runni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dynamic Memory Allocation
Memory management (also dynamic memory management, dynamic storage allocation, or dynamic memory allocation) is a form of resource management applied to computer memory. The essential requirement of memory management is to provide ways to dynamically allocate portions of memory to programs at their request, and free it for reuse when no longer needed. This is critical to any advanced computer system where more than a single process might be underway at any time. Several methods have been devised that increase the effectiveness of memory management. Virtual memory systems separate the memory addresses used by a process from actual physical addresses, allowing separation of processes and increasing the size of the virtual address space beyond the available amount of RAM using paging or swapping to secondary storage. The quality of the virtual memory manager can have an extensive effect on overall system performance. The system allows a computer to appear as if it may have more ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Static Variable
In computer programming, a static variable is a variable that has been allocated "statically", meaning that its lifetime (or "extent") is the entire run of the program. This is in contrast to shorter-lived automatic variables, whose storage is stack allocated and deallocated on the call stack; and in contrast to dynamically allocated objects, whose storage is allocated and deallocated in heap memory. Variable lifetime is contrasted with scope (where a variable can be used): "global" and "local" refer to scope, not lifetime, but scope often implies lifetime. In many languages, global variables are always static, but in some languages they are dynamic, while local variables are generally automatic, but may be static. In general, is the allocation of memory at compile time, before the associated program is executed, unlike dynamic memory allocation or automatic memory allocation where memory is allocated as required at run time. History Static variables date at least ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Automatic Variable
In computer programming, an automatic variable is a local variable which is allocated and deallocated automatically when program flow enters and leaves the variable's scope. The scope is the lexical context, particularly the function or block in which a variable is defined. Local data is typically (in most languages) invisible outside the function or lexical context where it is defined. Local data is also invisible and inaccessible to a ''called'' function,unless it is a nested function, which itself is ''defined'' along that local data but is not deallocated, coming back in scope as the execution thread returns to the caller. Automatic local variables primarily applies to recursive lexically-scoped languages.although they exist in a somewhat similar, but not identical, form also in recursive languages with dynamic scoping, such as older variants of LISP Automatic local variables are normally allocated in the stack frame of the procedure in which they are declared.unless ot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Application Binary Interface
An application binary interface (ABI) is an interface exposed by software that is defined for in-process machine code access. Often, the exposing software is a library, and the consumer is a program. An ABI is at a relatively low-level of abstraction. Interface compatibility depends on the target hardware and the software build toolchain. In contrast, an application programming interface (API) defines access in source code which is a relatively high-level, hardware-independent, and human-readable format. An API defines interface at the source code level, before compilation, whereas an ABI defines an interface to compiled code. API compatibility is generally the concern for system design and of the toolchain. However, a programmer may have to deal with an ABI directly when writing a program in a multiple languages or compilers. A complete ABI enables a program that supports an ABI to run without modification on multiple operating systems that provide the ABI. The targe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MIPS Architecture
MIPS (Microprocessor without Interlocked Pipelined Stages) is a family of reduced instruction set computer (RISC) instruction set architectures (ISA)Price, Charles (September 1995). ''MIPS IV Instruction Set'' (Revision 3.2), MIPS Technologies, Inc. developed by MIPS Computer Systems, now MIPS Technologies, based in the United States. There are multiple versions of MIPS, including MIPS I, II, III, IV, and V, as well as five releases of MIPS32/64 (for 32- and 64-bit implementations, respectively). The early MIPS architectures were 32-bit; 64-bit versions were developed later. As of April 2017, the current version of MIPS is MIPS32/64 Release 6. MIPS32/64 primarily differs from MIPS I–V by defining the privileged kernel mode System Control Coprocessor in addition to the user mode architecture. The MIPS architecture has several optional extensions: MIPS-3D, a simple set of floating-point SIMD instructions dedicated to 3D computer graphics; MDMX (MaDMaX), a more extensive i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PowerPC
PowerPC (with the backronym Performance Optimization With Enhanced RISC – Performance Computing, sometimes abbreviated as PPC) is a reduced instruction set computer (RISC) instruction set architecture (ISA) created by the 1991 Apple Inc., Apple–IBM–Motorola alliance, known as AIM alliance, AIM. PowerPC, as an evolving instruction set, has been named Power ISA since 2006, while the old name lives on as a trademark for some implementations of Power Architecture–based processors. Originally intended for personal computers, the architecture is well known for being used by Apple's desktop and laptop lines from 1994 until 2006, and in several videogame consoles including Microsoft's Xbox 360, Sony's PlayStation 3, and Nintendo's GameCube, Wii, and Wii U. PowerPC was also used for the Curiosity (rover), Curiosity and Perseverance (rover), Perseverance rovers on Mars and a variety of satellites. It has since become a niche architecture for personal computers, particularly with A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RISC-V
RISC-V (pronounced "risk-five") is an open standard instruction set architecture (ISA) based on established reduced instruction set computer (RISC) principles. The project commenced in 2010 at the University of California, Berkeley. It transferred to the RISC-V Foundation in 2015, and from there to RISC-V International, a Swiss non-profit entity, in November 2019. Similar to several other RISC ISAs, e.g. Amber (processor), Amber (ARMv2)(2001), SuperH#J_Core, J-Core(2015), OpenRISC(2000), or OpenSPARC(2005), RISC-V is offered under royalty-free open-source licenses. The documents defining the RISC-V instruction set architecture (ISA) are offered under a Creative Commons license or a BSD licenses, BSD License. Mainline support for RISC-V was added to the Linux 5.17 kernel in 2022, along with its toolchain. In July 2023, RISC-V, in its 64-bit computing, 64-bit variant called riscv64, was included as an official architecture of Linux distribution Debian, in its Debian version histor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gnulib
Gnulib, also called the GNU portability library, is a collection of software subroutines which are designed to be usable on many operating systems. The goal of the project is to make it easy for free software authors to make their software run on many operating systems. Since source is designed to be copied from gnulib, it is not a library per-se, as much as a collection of portable idioms to be used in other projects. Making a software package work on a system other than the original system it worked on is usually called "porting" the software to the new system, and a library is a collection of subroutines which can be added to new programs. Thus, Gnulib is the GNU project's portability library. It is primarily written for use by the GNU Project, but can be used by any free software project. See also * GLib * libiberty * Boost (C++ libraries) Boost, boosted or boosting may refer to: Science, technology and mathematics * Boost, positive manifold pressure in Turbocharger, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
