Programming with Intel Extended Memory 64 Technology: Migrating Software for Optimal 64-bit Performance

By Andrew Binstock

Glossary

64-bit mode: The mode in which 64-bit applications run on platforms with Intel EM64T.

See also compatibility mode.

aliasing: A situation in which two or more distinct references map to the same address in memory or in cache.
alignment: The need for data items to be located on specific boundaries in memory. Misaligned data can cause the system to hang in certain cases, but mostly it detrimentally affects performance. Padding helps keep data items aligned within aggregate data types.
associativity: The means by which a memory cache maps the main RAM to the smaller cache. It defines the way cache entries are looked up and found in a processor.
atomic: Operations that are indivisible (hence, the reference to the atom), meaning that all the operations must be completed or none of them can be. Typical atomic operations include database transactions and any operation that, if interrupted, would leave the software or the system in an unstable or corrupted state.
base address: The starting address of a segment.
big-endian: A way of storing values in memory that is favored by RISC processors. In this scheme, for example, a two-byte integer whose value is 0x012 3 is stored in consecutive bytes in memory as 01 23. The big-end (the most important bits) are stored in the lower addressed-byte, hence the name.

See also little endian.
cache coherency: The need for caches on separate processors to contain the same values with respect to a data item that is held...

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Programming with Intel Extended Memory 64 Technology: Migrating Software for Optimal 64-bit Performance