Level 1 cache, often called primary cache, is a static memory
integrated with processor core that is used to store information
recently accessed by a processor. Level 1 cache is often abbreviated
as L1 cache. The purpose of level 1 cache is to improve data access
speed in cases when the CPU accesses the same data multiple times.
For this reason access time of level 1 cache is always faster than
access time of system memory. The processor may have additional
level 2 and level 3 caches, albeit
those caches are always slower then the L1 cache.
In modern microprocessors primary cache is split into two caches of
equal size - one is used to store program data, and another is used to
store microprocessor instructions. Some old microprocessors utilized
"unified" primary cache, which was used to store both data and
instructions in the same cache.
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