The Cyrix 6x86 (codename M1) is a sixth-generation, 32-bit 80x86-compatible microprocessor designed by Cyrix and manufactured by IBM and SGS-Thomson. The range of Integer values that can be stored in 32 bits is 0 through 4294967295 or −2147483648 through 2147483647 using Two's complement encoding See also X86 assembly language The generic term x86 refers to the most commercially successful Instruction set architecture in the history of Personal A microprocessor incorporates most or all of the functions of a Central processing unit (CPU on a single Integrated Cyrix was a CPU manufacturer that began in 1978 in Richardson Texas as a specialist supplier of high-performance math co-processors for 286 and International Business Machines Corporation abbreviated IBM and nicknamed "Big Blue", is a multinational Computer Technology It was originally released in 1996.
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Architecture
The 6x86 combines aspects of both RISC and CISC. It has a superscalar, superpipelined core, and performs register renaming, speculative execution, out-of-order execution, and data dependency removal. A superscalar CPU architecture implements a form of parallelism called Instruction-level parallelism within a single processor Pipelining redirects here For HTTP pipelining see HTTP pipelining. In Computer engineering, register renaming refers to a technique usedto avoid unnecessary serialization of program operations imposed by the reuseof registers by those In Computer science, speculative execution is the execution of code, the result of which may not be needed In Computer engineering, out-of-order execution, OoOE, is a paradigm used in most high-performance Microprocessors to make use of cycles that A data dependency in computer science is a situation in which a program statement (instruction refers to the data of a preceding statement However, it continued to use native x86 execution, like Centaur's Winchip, but unlike competitors Intel and AMD who moved to RISC translation with Pentium Pro and K5. Centaur Technology is an x86 CPU design company now a wholly owned subsidiary of VIA Technologies, a member of the Formosa Plastics Group, The WinChip series was a low-power Socket 7 -based X86 processor designed by Centaur Technology and marketed by its parent company The Pentium Pro is a sixth-generation X86 -based Microprocessor developed and manufactured by Intel introduced in November 1995 The K5 was AMD's first x86 processor developed entirely in-house introduced in March 1996
With regards to internal caches, it has a 16-kibibyte primary cache and is socket-compatible with the Intel Pentium P54C. A kibibyte (a contraction of ki lo bi nary byte) is a unit of Information or Computer storage, established by the International A CPU socket or CPU slot is a connector on a computer's Motherboard that accepts a CPU and forms an electrical interface with it The Pentium brand refers to Intel 's single-core x86 Microprocessor based on the P5 fifth-generation Microarchitecture. It was also unique in that it was the only x86 design to incorporate a 256-byte Level 0 scratchpad cache. See also X86 assembly language The generic term x86 refers to the most commercially successful Instruction set architecture in the history of Personal It has six performance levels: PR 90+, PR 120+, PR 133+, PR 150+, PR 166+ and PR 200+. These performance levels do not map to the clock speed of the chip itself (for example, a PR 133+ ran at 110 MHz, a PR 166+ ran at 133 MHz, etc).
Note that the 6x86 and 6x86L weren't completely compatible with the Intel Pentium instruction set. The Pentium brand refers to Intel 's single-core x86 Microprocessor based on the P5 fifth-generation Microarchitecture. For this reason the chip identified itself as a 80486 and disabled the CPUID instruction by default. The Intel 486, otherwise known as the 80486 i486 or just 486 was the first tightly pipelined X86 design The CPUID Opcode is an instruction (its name derived from CPU IDentification for the X86 architecture CPUID support could be enabled by first enabling extended CCR registers then setting bit 7 in CCR4. The lack of full Pentium compatibility caused problems with some applications because programmers had begun to use Pentium-specific instructions. Some companies released patches for their products to make them function on the 6x86.
The first generation of 6x86 had heat problems. This was primarily caused by their relatively higher heat output than other CPUs of the day and, as such, computer builders sometimes did not equip them with adequate cooling. The CPUs topped out at around 25 W heat output (like the AMD K6), whereas the Pentium produced around 15 W of waste heat at its peak. The watt (symbol W) is the SI derived unit of power, equal to one Joule of energy per Second. The 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
6x86 is not multi-processor capable.
Revised cores
The 6x86L was later released by Cyrix to address heat issues; the L standing for low-power. Cyrix was a CPU manufacturer that began in 1978 in Richardson Texas as a specialist supplier of high-performance math co-processors for 286 and Another release of the 6x86, the 6x86MX, added MMX compatibility, introduced the EMMI instruction set, and quadrupled the primary cache size to 64 kibibytes. MMX is a single instruction multiple data (SIMD Instruction set designed by Intel, introduced in 1997 in their Pentium line of European Master in Molecular Imaging (EMMI is the first Master program in Europe (M1 + M2 exclusively dedicated to Molecular imaging. This chip was later renamed MII, to better compete with the Pentium II processor.
Performance
It has been speculated by experts that 6x86 was designed to perform well specifically on business-oriented benchmarks of the time, most notably Ziff-Davis' Winstone benchmark. This article is about the use of benchmarks in computing for other uses see Benchmark. [1] Winstone ran various speed tests using several popular applications. It was one of the leading benchmarks during the mid-'90s and was used in some leading magazines, such as Computer Shopper and PC Magazine, as a deciding factor for system ratings. PC Magazine (sometimes referred to as PC Mag) is a Computer magazine that is published monthly in the United States (until 2008 it was published
The 6x86's integer performance was fantastic. As said earlier, Cyrix used a PR rating (Performance Rating) to relate their performance to the Intel Pentium Classic (pre-P55C), because a 6x86 at a lower clock rate outperformed the higher-clocked Pentium. The PR ( P erformance R ating system was developed by AMD in the mid-1990s as a method of comparing their X86 processors to those of rival The Pentium brand refers to Intel 's single-core x86 Microprocessor based on the P5 fifth-generation Microarchitecture. For example, a 133 MHz 6x86 will outperform a Pentium Classic at 166 MHz, and as a result Cyrix could market the 133 MHz chip as being a Pentium 166's equal. A PR rating was also necessary because the 6x86 could not clock as high as Pentium and maintain equivalent manufacturing yields, so it was critical to establish the slower clock speeds as equal in the minds of the consumer. The PR rating was not an entirely truthful representation of the 6x86's performance, however.
While it can be simply said that its integer performance is excellent, the same can not be said with regard to its floating point performance. The FPU is considerably less robust than that of the Pentium (let alone the P6 FPU. A floating point unit (FPU is a part of a Computer system specially designed to carry out operations on Floating point numbers The P6 Microarchitecture is the sixth generation Intel X86 Microprocessor architecture released in 1995. ) During the 6x86's development, the majority of applications (office software) performed almost entirely integer operations. In Computing, an office suite, sometimes called an office software suite or productivity suite is a Software suite intended to be used by typical The designers foresaw that future applications would most likely maintain this instruction focus. So, to optimize the chip's performance for what they believed to be the most likely application of the CPU, the integer execution resources received most of the transistor budget.
The poor FPU performance of the 6x86 can be mostly attributed to major FPU instructions taking at least 4 clock cycles and that it was not pipelined. Pipelining redirects here For HTTP pipelining see HTTP pipelining. It was not much faster than a 486 FPU at the same clock speed. The popularity of the Pentium caused many software developers to hand-optimize code in assembly language, to take advantage of the Pentium's pipelined and lower latency FPU. A software developer is a person or organization concerned with facets of the software development process wider than design and coding a somewhat broader scope of See the terminology section below for information regarding inconsistent use of the terms assembly and assembler For example, the highly anticipated first person shooter Quake used highly-optimized assembly code designed almost entirely around the Pentium's FPU. A first-person shooter ( FPS) is an action Video game from the Shooter game The initial development of Maze War Quake is a First-person shooter Computer game that was released by Id Software on June 22, 1996. As a result, the Pentium significantly outperformed other CPUs in the game. Fortunately for the 6x86 (and AMD K6), many games continued to be integer-based throughout the chip's lifetime.
Cyrix MII
The 6x86 successor, MII, was late to market, and couldn't scale well in clock speed. Cyrix had made a mistake with 6x86, similar to what AMD had done with their K5; design a chip far more focused on integer per-clock performance superiority than clock scalability. As such, 6x86 and MII were forced to compete at the low-end of the market because AMD K6 and Intel Pentium II were always at least one step ahead on clock speed. This, combined with the limited floating point unit, and an integer section that was at best on-par with the newer P6 and K6 chips, Cyrix could no longer compete in performance. The P6 Microarchitecture is the sixth generation Intel X86 Microprocessor architecture released in 1995.
External links
- Cyrix 6x86 ("M1") at PCGuide
- cpu-collection.de Cyrix 6x86 processor images and descriptions
- Paul Hsieh's 6th Generation x86 CPU Comparison in-depth analysis of 6th generation x86 CPUs, including the 6x86MX.
- Cyrix M1 stats at Sandpile. org
This article was originally based on material from the Free On-line Dictionary of Computing, which is licensed under the GFDL. The Free On-line Dictionary of Computing ( FOLDOC) is an online searchable encyclopedic Dictionary of Computing subjects The GNU Free Documentation License ( GNU FDL or simply GFDL) is a Copyleft License for free documentation designed by the Free Software
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