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Memory Type Range Register
Memory type range registers (MTRRs) are a set of processor supplementary capability control registers that provide system software with control of how accesses to memory ranges by the CPU are cached. It uses a set of programmable model-specific registers (MSRs) which are special registers provided by most modern CPUs. Possible access modes to memory ranges can be uncached, write-through, write-combining, write-protect, and write-back. In write-back mode, writes are written to the CPU's cache and the cache is marked dirty, so that its contents are written to memory later. Write-combining allows bus write transfers to be combined into a larger transfer before bursting them over the bus to allow more efficient writes to system resources like graphics card memory. This often increases the speed of image write operations by several times, at the cost of losing the simple sequential read/write semantics of normal memory. Additional bits which are provided on some computer archit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Processor Supplementary Capability
A processor supplementary capability is a feature that has been added to an existing central processing unit (CPU) design after the initial introduction of that design to the marketplace. A supplementary capability increases the usefulness of the processor design, allowing it to compete more favorably with competitors and giving consumers a reason to upgrade, while retaining backwards compatibility with the original design. The CPU supplementary instruction capability does not as a rule apply to 8 or 16 bit CPUs, as many of these CPUs are used mostly as microcontrollers. On modern 32 and 64 bit CPUs the ''processor supplementary capability'' does not extend to Floating Point Units (FPUs) or Memory Management Units (MMUs) as these are considered to be fundamental core functionalities. Extensions to the core functionalities of the MMU and FPU may be considered CPU extensions however. Historical reasoning The supplementary instructions feature has always been assumed to mean ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X86 Architecture
x86 (also known as 80x86 or the 8086 family) is a family of complex instruction set computer (CISC) instruction set architectures initially developed by Intel based on the Intel 8086 microprocessor and its 8088 variant. The 8086 was introduced in 1978 as a fully 16-bit extension of Intel's 8-bit 8080 microprocessor, with memory segmentation as a solution for addressing more memory than can be covered by a plain 16-bit address. The term "x86" came into being because the names of several successors to Intel's 8086 processor end in "86", including the 80186, 80286, 80386 and 80486 processors. The term is not synonymous with IBM PC compatibility, as this implies a multitude of other computer hardware. Embedded systems and general-purpose computers used x86 chips before the PC-compatible market started, some of them before the IBM PC (1981) debut. , most desktop and laptop computers sold are based on the x86 architecture family, while mobile categories such as smartphones o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Address Range Registers
Address-range registers (ARR) are control registers of the Cyrix 6x86, 6x86MX and MII processors that are used as a control mechanism which provides system software with control of how accesses to memory ranges by the CPU are cached, similar to what memory type range registers (MTRRs) provide on other implementations of the x86 architecture. See also * Write barrier * Page attribute table The page attribute table (PAT) is a processor supplementary capability extension to the page table format of certain x86 and x86-64 microprocessors. Like memory type range registers (MTRRs), they allow for fine-grained control over how areas of ... References Digital registers {{compu-hardware-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyrix MII
The 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. 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. This would later prove to be a strategic mistake, as the popularity of the P5 Pentium caused many software developers to hand-optimize code in assembly language, to take advantage of the P5 Pentium's tightly pipelined and lower latency FPU. For example, the highly anticip ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
6x86MX
The 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, Intel's Pentium (original), 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. 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. This would later prove to be a strategic mistake, as the popularity of the P5 Pentium caused many software developers to hand-optimize code in X86 assembly language, assembly language, to take advantage of the P5 Pentium's tightly pipelined and lowe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
6x86
The 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. 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. This would later prove to be a strategic mistake, as the popularity of the P5 Pentium caused many software developers to hand-optimize code in assembly language, to take advantage of the P5 Pentium's tightly pipelined and lower latency FPU. For example, the highly anticipat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyrix
Cyrix 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. Their release sparked a lengthy series of lawsuits with Intel while their foundry partner IBM was releasing the same designs under their own branding. The combination of these events led Cyrix to begin losing money, and the company merged with National Semiconductor on 11 November 1997. National released Cyrix's latest designs under the MediaGX name and then an updated version as Geode in 1999. National sold the line to AMD in August 2003 where it was known as Geode. The line was discontinued in 2019. History At ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentium II
The Pentium II brand refers to Intel's sixth-generation microarchitecture (" P6") and x86-compatible microprocessors introduced on May 7, 1997. Containing 7.5 million transistors (27.4 million in the case of the mobile Dixon with 256 KB L2 cache), the Pentium II featured an improved version of the first ''P6''-generation core of the Pentium Pro, which contained 5.5 million transistors. However, its L2 cache subsystem was a downgrade when compared to the Pentium Pros. It is a single-core microprocessor. In 1998, Intel stratified the Pentium II family by releasing the Pentium II-based Celeron line of processors for low-end workstations and the Pentium II Xeon line for servers and high-end workstations. The Celeron was characterized by a reduced or omitted (in some cases present but disabled) on-die full-speed L2 cache and a 66 MT/s FSB. The Xeon was characterized by a range of full-speed L2 cache (from 512 KB to 2048 KB), a 100 MT/s FSB, a different physical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentium Pro
The 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. Later, it was reduced to a more narrow role as a server and high-end desktop processor and was used in supercomputers like ASCI Red, the first computer to reach the trillion ''floating point operations per second'' (teraFLOPS) performance mark. The Pentium Pro was capable of both dual- and quad-processor configurations. It only came in one form factor, the relatively large rectangular Socket 8. The Pentium Pro was succeeded by the Pentium II Xeon in 1998. Microarchitecture The lead architect of Pentium Pro was Fred Pollack who was specialized in supe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
P6 (microarchitecture)
The P6 microarchitecture is the sixth-generation Intel x86 microarchitecture, implemented by the Pentium Pro microprocessor that was introduced in November 1995. It is frequently referred to as i686. It was succeeded by the NetBurst microarchitecture in 2000, but eventually revived in the Pentium M line of microprocessors. The successor to the Pentium M variant of the P6 microarchitecture is the Core microarchitecture which in turn is also derived from P6. P6 was used within Intel's mainstream offerings from the Pentium Pro to Pentium III, and was widely known for low power consumption, excellent integer performance, and relatively high instructions per cycle (IPC). The P6 line of processing cores was succeeded by the NetBurst (P68) architecture which appeared with the introduction of Pentium 4. The P6 core was the sixth generation Intel microprocessor in the x86 line. The first implementation of the P6 core was the Pentium Pro CPU in 1995, the immediate successor to the or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peripheral Component Interconnect
Peripheral Component Interconnect (PCI) is a local computer bus for attaching hardware devices in a computer and is part of the PCI Local Bus standard. The PCI bus supports the functions found on a processor bus but in a standardized format that is independent of any given processor's native bus. Devices connected to the PCI bus appear to a bus master to be connected directly to its own bus and are assigned addresses in the processor's address space. It is a parallel bus, synchronous to a single bus clock. Attached devices can take either the form of an integrated circuit fitted onto the motherboard (called a ''planar device'' in the PCI specification) or an expansion card that fits into a slot. The PCI Local Bus was first implemented in IBM PC compatibles, where it displaced the combination of several slow Industry Standard Architecture (ISA) slots and one fast VESA Local Bus (VLB) slot as the bus configuration. It has subsequently been adopted for other computer types. Typic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Real Mode
Real mode, also called real address mode, is an operating mode of all x86-compatible CPUs. The mode gets its name from the fact that addresses in real mode always correspond to real locations in memory. Real mode is characterized by a 20-bit segmented memory address space (giving 1 MB of addressable memory) and unlimited direct software access to all addressable memory, I/O addresses and peripheral hardware. Real mode provides no support for memory protection, multitasking, or code privilege levels. Before the release of the 80286, which introduced protected mode, real mode was the only available mode for x86 CPUs; and for backward compatibility, all x86 CPUs start in real mode when reset, though it is possible to emulate real mode on other systems when starting on other modes. History The 286 architecture introduced protected mode, allowing for (among other things) hardware-level memory protection. Using these new features, however, required a new operating system that was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
