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Is a generalisation of normal compare-and-swap. It can be used to atomically swap an arbitrary number of arbitrarily located memory locations. Usually, multi-word compare-and-swap is implemented in software using normal double-wide compare-and-swap operations. [16] The drawback of this approach is a lack of scalability. Persistent compare-and-swap
The simplest and probably most widely used method to swap two variables is to use a third temporary variable: define swap (x, y) temp := x x := y y := temp While this is conceptually simple and in many cases the only convenient way to swap two variables, it uses extra memory.
Double compare-and-swap (DCAS or CAS2) is an atomic primitive proposed to support certain concurrent programming techniques. DCAS takes two not necessarily contiguous memory locations and writes new values into them only if they match pre-supplied "expected" values; as such, it is an extension of the much more popular compare-and-swap (CAS ...
In computer science, read–modify–write is a class of atomic operations (such as test-and-set, fetch-and-add, and compare-and-swap) that both read a memory location and write a new value into it simultaneously, either with a completely new value or some function of the previous value.
Software transactional memory provides transactional memory semantics in a software runtime library or the programming language, [9] and requires minimal hardware support (typically an atomic compare and swap operation, or equivalent). As the downside, software implementations usually come with a performance penalty, when compared to hardware ...
Using the XOR swap algorithm to exchange nibbles between variables without the use of temporary storage. In computer programming, the exclusive or swap (sometimes shortened to XOR swap) is an algorithm that uses the exclusive or bitwise operation to swap the values of two variables without using the temporary variable which is normally required.
In computer science, the fetch-and-add (FAA) CPU instruction atomically increments the contents of a memory location by a specified value.. That is, fetch-and-add performs the following operation: increment the value at address x by a, where x is a memory location and a is some value, and return the original value at x.
The Java memory model describes how threads in the Java programming language interact through memory. Together with the description of single-threaded execution of code, the memory model provides the semantics of the Java programming language.