256EinträgeTabelle

256EinträgeTabelle is a term used in computing to describe a data table containing exactly 256 elements. The name reflects the fixed size and the common use of an 8-bit index, allowing 256 distinct positions numbered 0 to 255. Each entry can hold a value of various types, depending on the language and purpose, such as numbers, bytes, or pointers.

Such tables are typically implemented as one-dimensional arrays. They enable fast lookups because the index is a single byte, avoiding more expensive search operations. They are widely used in systems that operate on byte-oriented data, where an 8-bit address space naturally yields 256 slots. The fixed size supports predictable memory usage and cache-friendly access patterns.

Typical applications include color palettes for 8-bit images, where each entry specifies a color; substitution or mapping tables in cryptography or data processing (for example, substitution boxes in block ciphers); character encoding mappings from extended ASCII or code pages to Unicode; and small decoders or automata in software and firmware.

Implementation notes emphasize that all 256 entries should be defined to avoid uninitialized data, and using unsigned indices prevents negative indexing. The memory footprint is predictable, and tables can be declared as constants for performance. Variants and related concepts include larger tables with sizes that are powers of two, but 256 remains common due to its alignment with 8-bit data. In hardware and embedded systems, 256-entry lookups appear in ROMs, firmware, GPUs, and network devices where fast, deterministic mappings are required.