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ARM926EJ
ARM9 is a group of 32-bit RISC ARM processor cores licensed by ARM Holdings for microcontroller use. The ARM9 core family consists of ARM9TDMI, ARM940T, ARM9E-S, ARM966E-S, ARM920T, ARM922T, ARM946E-S, ARM9EJ-S, ARM926EJ-S, ARM968E-S, ARM996HS. ARM9 cores were released from 1998 to 2006, and no longer recommended for new IC designs; newer alternatives are ARM Cortex-M cores. Overview With this design generation, ARM moved from a von Neumann architecture (Princeton architecture) to a (modified; meaning split cache) Harvard architecture with separate instruction and data buses (and caches), significantly increasing its potential speed. Most silicon chips integrating these cores will package them as modified Harvard architecture chips, combining the two address buses on the other side of separated CPU caches and tightly coupled memories. There are two subfamilies, implementing different ARM architecture versions. Differences from ARM7 cores Key improvements over ARM7 cores, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jazelle
Jazelle DBX (direct bytecode execution) is an extension that allows some ARM processors to execute Java bytecode in hardware as a third execution state alongside the existing ARM and Thumb modes. Jazelle functionality was specified in the ARMv5TEJ architecture and the first processor with Jazelle technology was the ARM926EJ-S. Jazelle is denoted by a "J" appended to the CPU name, except for post-v5 cores where it is required (albeit only in trivial form) for architecture conformance. Jazelle RCT (Runtime Compilation Target) is a different technology based on ThumbEE mode; it supports ahead-of-time (AOT) and just-in-time (JIT) compilation with Java and other execution environments. The most prominent use of Jazelle DBX is by manufacturers of mobile phones to increase the execution speed of Java ME games and applications. A Jazelle-aware Java virtual machine (JVM) will attempt to run Java bytecode in hardware, while returning to the software for more complicated, or lesser-used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ARM Holdings
Arm Holdings plc (formerly an acronym for Advanced RISC Machines and originally Acorn RISC Machine) is a British semiconductor and software design company based in Cambridge, England, whose primary business is the design of central processing unit (CPU) cores that implement the ARM architecture family of instruction sets. It also designs other chips, provides software development tools under the DS-5, RealView and Keil brands, and provides systems and platforms, system-on-a-chip (SoC) infrastructure and software. As a "holding" company, it also holds shares of other companies. Since 2016, it has been majority owned by Japanese conglomerate SoftBank Group. While ARM CPUs first appeared in the Acorn Archimedes, a desktop computer, today's systems include mostly embedded systems, including ARM CPUs used in virtually all modern smartphones. Processors based on designs licensed from Arm, or designed by licensees of one of the ARM instruction set architectures, are used in all ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NOR Flash
Flash memory is an electronic non-volatile computer memory storage medium that can be electrically erased and reprogrammed. The two main types of flash memory, NOR flash and NAND flash, are named for the NOR and NAND logic gates. Both use the same cell design, consisting of floating-gate MOSFETs. They differ at the circuit level, depending on whether the state of the bit line or word lines is pulled high or low; in NAND flash, the relationship between the bit line and the word lines resembles a NAND gate; in NOR flash, it resembles a NOR gate. Flash memory, a type of floating-gate memory, was invented by Fujio Masuoka at Toshiba in 1980 and is based on EEPROM technology. Toshiba began marketing flash memory in 1987. EPROMs had to be erased completely before they could be rewritten. NAND flash memory, however, may be erased, written, and read in blocks (or pages), which generally are much smaller than the entire device. NOR flash memory allows a single machine word to be wri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Memory Management Unit
A memory management unit (MMU), sometimes called paged memory management unit (PMMU), is a computer hardware unit that examines all references to computer memory, memory, and translates the memory addresses being referenced, known as virtual memory addresses, into physical addresses in main memory. In modern systems, programs generally have addresses that access the theoretical maximum memory of the computer architecture, 32 or 64 bits. The MMU maps the addresses from each program into separate areas in physical memory, which is generally much smaller than the theoretical maximum. This is possible because programs rarely use large amounts of memory at any one time. Most modern operating systems (OS) work in concert with an MMU to provide virtual memory (VM) support. The MMU tracks memory use in fixed-size blocks known as ''pages''. If a program refers to a location in a page that is not in physical memory, the MMU sends an interrupt to the operating system. The OS selects a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ARMv4T
ARM (stylised in lowercase as arm, formerly an acronym for Advanced RISC Machines and originally Acorn RISC Machine) is a family of RISC instruction set architectures (ISAs) for computer processors. Arm Holdings develops the ISAs and licenses them to other companies, who build the physical devices that use the instruction set. It also designs and licenses cores that implement these ISAs. Due to their low costs, low power consumption, and low heat generation, ARM processors are useful for light, portable, battery-powered devices, including smartphones, laptops, and tablet computers, as well as embedded systems. However, ARM processors are also used for desktops and servers, including Fugaku, the world's fastest supercomputer from 2020 to 2022. With over 230 billion ARM chips produced, , ARM is the most widely used family of instruction set architectures. There have been several generations of the ARM design. The original ARM1 used a 32-bit internal structure but had a 2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ARM7TDMI
ARM7 is a group of 32-bit RISC ARM processor cores licensed by ARM Holdings for microcontroller use. The ARM7 core family consists of ARM700, ARM710, ARM7DI, ARM710a, ARM720T, ARM740T, ARM710T, ARM7TDMI, ARM7TDMI-S, ARM7EJ-S. The ARM7TDMI and ARM7TDMI-S were the most popular cores of the family. ARM7 cores were released from 1993 to 2001 and no longer recommended for new IC designs; newer alternatives are ARM Cortex-M cores. Overview This generation introduced the Thumb 16-bit instruction set providing improved code density compared to previous designs. The most widely used ARM7 designs implement the ARMv4T architecture, but some implement ARMv3 or ARMv5TEJ. ARM7TDMI has 37 registers (31 GPR and 6 SPR). All these designs use a Von Neumann architecture, thus the few versions containing a cache do not separate data and instruction caches. Some ARM7 cores are obsolete. One historically significant model, the ARM7DI"ARM7DI Data Sheet"; Document Number ARM DDI 0027D; Issued: De ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multiprocessor Programming
Multiprocessing (MP) is the use of two or more central processing units (CPUs) within a single computer system. The term also refers to the ability of a system to support more than one processor or the ability to allocate tasks between them. There are many variations on this basic theme, and the definition of multiprocessing can vary with context, mostly as a function of how CPUs are defined ( multiple cores on one die, multiple dies in one package, multiple packages in one system unit, etc.). A multiprocessor is a computer system having two or more processing units (multiple processors) each sharing main memory and peripherals, in order to simultaneously process programs. A 2009 textbook defined multiprocessor system similarly, but noted that the processors may share "some or all of the system’s memory and I/O facilities"; it also gave tightly coupled system as a synonymous term. At the operating system level, ''multiprocessing'' is sometimes used to refer to the execution ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Symmetric Multiprocessing
Symmetric multiprocessing or shared-memory multiprocessing (SMP) involves a multiprocessor computer hardware and software architecture where two or more identical processors are connected to a single, shared main memory, have full access to all input and output devices, and are controlled by a single operating system instance that treats all processors equally, reserving none for special purposes. Most multiprocessor systems today use an SMP architecture. In the case of multi-core processors, the SMP architecture applies to the cores, treating them as separate processors. Professor John D. Kubiatowicz considers traditionally SMP systems to contain processors without caches. Culler and Pal-Singh in their 1998 book "Parallel Computer Architecture: A Hardware/Software Approach" mention: "The term SMP is widely used but causes a bit of confusion. ..The more precise description of what is intended by SMP is a shared memory multiprocessor where the cost of accessing a memory location ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asymmetric Multiprocessing
An asymmetric multiprocessing (AMP or ASMP) system is a multiprocessor computer system where not all of the multiple interconnected central processing units (CPUs) are treated equally. For example, a system might allow (either at the hardware or operating system level) only one CPU to execute operating system code or might allow only one CPU to perform I/O operations. Other AMP systems might allow any CPU to execute operating system code and perform I/O operations, so that they were symmetric with regard to processor roles, but attached some or all peripherals to particular CPUs, so that they were asymmetric with respect to the peripheral attachment. Asymmetric multiprocessing was the only method for handling multiple CPUs before symmetric multiprocessing (SMP) was available. It has also been used to provide less expensive options on systems where SMP was available. Background and history For the room-size computers of the 1960s and 1970s, a cost-effective way to increase comput ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multicore Processor
A multi-core processor (MCP) is a microprocessor on a single integrated circuit (IC) with two or more separate central processing units (CPUs), called ''cores'' to emphasize their multiplicity (for example, ''dual-core'' or ''quad-core''). Each core reads and executes program instructions, specifically ordinary CPU instructions (such as add, move data, and branch). However, the MCP can run instructions on separate cores at the same time, increasing overall speed for programs that support multithreading or other parallel computing techniques. Manufacturers typically integrate the cores onto a single IC die, known as a ''chip multiprocessor'' (CMP), or onto multiple dies in a single chip package. As of 2024, the microprocessors used in almost all new personal computers are multi-core. A multi-core processor implements multiprocessing in a single physical package. Designers may couple cores in a multi-core device tightly or loosely. For example, cores may or may not share ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Verilog
Verilog, standardized as IEEE 1364, is a hardware description language (HDL) used to model electronic systems. It is most commonly used in the design and verification of digital circuits, with the highest level of abstraction being at the register-transfer level. It is also used in the verification of analog circuits and mixed-signal circuits, as well as in the design of genetic circuits. In 2009, the Verilog standard (IEEE 1364-2005) was merged into the SystemVerilog standard, creating IEEE Standard 1800-2009. Since then, Verilog has been officially part of the SystemVerilog language. The current version is IEEE standard 1800-2023. Overview Hardware description languages such as Verilog are similar to software programming languages because they include ways of describing the propagation time and signal strengths (sensitivity). There are two types of assignment operators; a blocking assignment (=), and a non-blocking (>>. A generate–endgenerate construct (similar to V ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
