Von Neumann programming languages
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A von Neumann language in computing is a programming language that is a high-level abstract isomorphic copy of a von Neumann architecture.[1] As of 2009[update], most current programming languages fit into this description[citation needed], likely as a consequence of the extensive domination of the von Neumann computer architecture during the past 50 years.
The differences between Fortran, C, and even Java, although considerable, are ultimately constrained by all three being based on the programming style of the von Neumann computer.[citation needed] If, for example, Java objects were all executed in parallel with asynchronous message passing and attribute-based declarative addressing, then Java would not be in the group.
The isomorphism between von Neumann programming languages and architectures is in the following manner:
- program variables ↔ computer storage cells
- control statements ↔ computer test-and-jump instructions
- assignment statements ↔ fetching, storing instructions
- expressions ↔ memory reference and arithmetic instructions.
Criticism
Backus claimed that by 1978 there existed in
Presence in modern systems
Many modern processors now contain multiple processing cores, and multi-threaded programming is usually the most efficient way to use more computational power in a single program. Some modern processors are highly optimized with techniques including out-of-order execution, but with complex logic to detect when this can be done without violating the von Neumann semantics of the logical programming model. Separate instruction and data caches are widely used, making the hardware a Modified Harvard architecture, but again with logic to detect cases where the optimization fails, to be able to execute self-modifying code.
Some specialized processors (including
Many widely used programming languages such as C, C++ and Java have ceased to be strictly von Neumann by adding support for parallel processing, in the form of threads. However, most of the categorically non-von Neumann languages are also functional languages and have not achieved widespread use.
See also
References
- . Retrieved 15 July 2023.
- ^ IBM Archives: John Backus