Out-of-order executionIn computer engineering, out-of-order execution (or more formally dynamic execution) is a paradigm used in most high-performance central processing units to make use of instruction cycles that would otherwise be wasted. In this paradigm, a processor executes instructions in an order governed by the availability of input data and execution units, rather than by their original order in a program. In doing so, the processor can avoid being idle while waiting for the preceding instruction to complete and can, in the meantime, process the next instructions that are able to run immediately and independently.
NexGenNexGen, Inc. was a private semiconductor company based in Milpitas, California, that designed x86 microprocessors until it was purchased by AMD in 1996. NexGen was a fabless design house that designed its chips but relied on other companies for production. NexGen's chips were produced by IBM's Microelectronics division in Burlington, Vermont alongside PowerPC and DRAM parts. The company was best known for the unique implementation of the x86 architecture in its processors.
Socket 7Socket 7 is a physical and electrical specification for an x86-style CPU socket on a personal computer motherboard. It was released in June 1995. The socket supersedes the earlier Socket 5, and accepts P5 Pentium microprocessors manufactured by Intel, as well as compatibles made by Cyrix/IBM, AMD, IDT and others. Socket 7 was the only socket that supported a wide range of CPUs from different manufacturers and a wide range of speeds.
CyrixCyrix Corporation was a microprocessor developer that was founded in 1988 in Richardson, Texas, as a specialist supplier of floating point units for 286 and 386 microprocessors. The company was founded by Tom Brightman and Jerry Rogers. In 1992, Cyrix introduced its own i386 compatible processors, the 486SLC and 486DLC. These were higher performance than the Intel parts, but lower price. They were primarily marketed to users looking to upgrade existing machines.
Register renamingIn computer architecture, register renaming is a technique that abstracts logical registers from physical registers. Every logical register has a set of physical registers associated with it. When a machine language instruction refers to a particular logical register, the processor transposes this name to one specific physical register on the fly. The physical registers are opaque and cannot be referenced directly but only via the canonical names.
Cyrix 6x86The Cyrix 6x86 is a line of sixth-generation, 32-bit x86 microprocessors designed and released by Cyrix in 1995. Cyrix, being a fabless company, had the chips manufactured by IBM and SGS-Thomson. The 6x86 was made as a direct competitor to Intel's Pentium microprocessor line, and was pin compatible. During the 6x86's development, the majority of applications (office software as well as games) performed almost entirely integer operations. The designers foresaw that future applications would most likely maintain this instruction focus.
CPU cacheA CPU cache is a hardware cache used by the central processing unit (CPU) of a computer to reduce the average cost (time or energy) to access data from the main memory. A cache is a smaller, faster memory, located closer to a processor core, which stores copies of the data from frequently used main memory locations. Most CPUs have a hierarchy of multiple cache levels (L1, L2, often L3, and rarely even L4), with different instruction-specific and data-specific caches at level 1.
WinChipThe WinChip series was a low-power Socket 7-based x86 processor designed by Centaur Technology and marketed by its parent company IDT. The design of the WinChip was quite different from other processors of the time. Instead of a large gate count and die area, IDT, using its experience from the RISC processor market, created a small and electrically efficient processor similar to the 80486, because of its single pipeline and in-order execution microarchitecture.
Pentium ProThe Pentium Pro is a sixth-generation x86 microprocessor developed and manufactured by Intel and introduced on November 1, 1995. It introduced the P6 microarchitecture (sometimes termed i686) and was originally intended to replace the original Pentium in a full range of applications. While the Pentium and Pentium MMX had 3.1 and 4.5 million transistors, respectively, the Pentium Pro contained 5.5 million transistors.
AMD K6The K6 microprocessor was launched by AMD in 1997. The main advantage of this particular microprocessor is that it was designed to fit into existing desktop designs for Pentium-branded CPUs. It was marketed as a product that could perform as well as its Intel Pentium II equivalent but at a significantly lower price. The K6 had a considerable impact on the PC market and presented Intel with serious competition. The AMD K6 is a superscalar P5 Pentium-class microprocessor, manufactured by AMD, which superseded the K5.