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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] |
Control Register
A control register is a processor register which changes or controls the general behavior of a CPU or other digital device. Common tasks performed by control registers include interrupt control, switching the addressing mode, paging control, and coprocessor control. Control registers in x86 series CR0 The CR0 register is 32 bits long on the 386 and higher processors. On x64 processors in long mode, it (and the other control registers) is 64 bits long. CR0 has various control flags that modify the basic operation of the processor. Register CR0 is the 32 Bit version of the old Machine Status Word (MSW) register. The MSW register was expanded to the Control Register with the appearance of the i386 processor. CR1 Reserved, the CPU will throw a # UD exception when trying to access it. CR2 Contains a value called Page Fault Linear Address (PFLA). When a page fault occurs, the address the program attempted to access is stored in the CR2 register. CR3 Used when virtual addr ... [...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] |
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] |
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] |
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] |
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] |
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] |
Write Barrier
In operating systems, write barrier is a mechanism for enforcing a particular ordering in a sequence of writes to a storage system in a computer system. For example, a write barrier in a file system is a mechanism (program logic) that ensures that in-memory file system state is written out to persistent storage in the correct order. In Garbage collection A write barrier in a Garbage collection (computer science), garbage collector is a fragment of code emitted by the compiler immediately before every store operation to ensure that (e.g.) generational invariants are maintained. In Computer storage A write barrier in a memory hierarchy, memory system, also known as a memory barrier, is a hardware-specific intrinsic function, compiler intrinsic that ensures that all preceding memory operations happened-before, "happen before" all subsequent ones. See also * Native Command Queuing References External links Barriers and journaling filesystems (LWN.net, May 21, 2008) Co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 memory are cached, and are a companion feature to the MTRRs. Unlike MTRRs, which provide the ability to manipulate the behavior of caching for a limited number of fixed physical address ranges, Page Attribute Tables allow for such behavior to be specified on a per-page basis, greatly increasing the ability of the operating system to select the most efficient behavior for any given task. Processors The PAT is available on Pentium III The Pentium III (marketed as Intel Pentium III Processor, informally PIII or P3) brand refers to Intel's 32-bit x86 desktop and mobile CPUs based on the sixth-generation P6 microarchitecture introduced on February 28, 1999. The brand's initial ... and newer CPUs, and on non-Intel CPUs. See also * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
