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116-596: Models in this series use one of various 32-bit MIPS processors . All WRT54G models support Fast Ethernet for wired data links , and 802.11b/g for wireless data links. The original WRT54G was first released in December 2002. It has a 4+1 port network switch (the Internet/WAN port is part of the same internal network switch, but on a different VLAN ). The devices have two removable antennas connected through Reverse Polarity TNC connectors. The WRT54GC router

232-427: A branch delay slot . Unless the branch delay slot is filled by an instruction performing useful work, an nop is substituted. MIPS I branch instructions compare the contents of a GPR (rs) against zero or another GPR (rt) as signed integers and branch if the specified condition is true. Control is transferred to the address computed by shifting the 16-bit offset left by two bits, sign-extending the 18-bit result, and adding

348-516: A communications subsystem to connect, control, direct and interface between these functional modules. An SoC must have at least one processor core , but typically an SoC has more than one core. Processor cores can be a microcontroller , microprocessor (μP), digital signal processor (DSP) or application-specific instruction set processor (ASIP) core. ASIPs have instruction sets that are customized for an application domain and designed to be more efficient than general-purpose instructions for

464-402: A load delay slot . The instruction in the load delay slot cannot use the data loaded by the load instruction. The load delay slot can be filled with an instruction that is not dependent on the load; a nop is substituted if such an instruction cannot be found. MIPS I has instructions to perform addition and subtraction. These instructions source their operands from two GPRs (rs and rt), and write

580-447: A memory hierarchy and cache hierarchy . In the mobile computing market, this is common, but in many low-power embedded microcontrollers, this is not necessary. Memory technologies for SoCs include read-only memory (ROM), random-access memory (RAM), Electrically Erasable Programmable ROM ( EEPROM ) and flash memory . As in other computer systems, RAM can be subdivided into relatively faster but more expensive static RAM (SRAM) and

696-494: A microcontroller , microprocessor or perhaps several processor cores with peripherals like a GPU , Wi-Fi and cellular network radio modems or one or more coprocessors . Similar to how a microcontroller integrates a microprocessor with peripheral circuits and memory, an SoC can be seen as integrating a microcontroller with even more advanced peripherals . Compared to a multi-chip architecture, an SoC with equivalent functionality will have reduced power consumption as well as

812-660: A netlist describing the design as a physical circuit and its interconnections. These netlists are combined with the glue logic connecting the components to produce the schematic description of the SoC as a circuit which can be printed onto a chip. This process is known as place and route and precedes tape-out in the event that the SoCs are produced as application-specific integrated circuits (ASIC). SoCs must optimize power use , area on die , communication, positioning for locality between modular units and other factors. Optimization

928-399: A semiconductor foundry . This process is called functional verification and it accounts for a significant portion of the time and energy expended in the chip design life cycle , often quoted as 70%. With the growing complexity of chips, hardware verification languages like SystemVerilog , SystemC , e , and OpenVera are being used. Bugs found in the verification stage are reported to

1044-492: A 32-bit ABI that resembles N32 more. A 1995 conference came up with MIPS EABI, for which the 32-bit version was quite similar. EABI inspired MIPS Technologies to propose a more radical "NUBI" ABI additionally reuse argument registers for the return value. MIPS EABI is supported by GCC but not LLVM, and neither supports NUBI. System on a chip A system on a chip or system-on-chip ( SoC / ˌ ˈ ɛ s oʊ s iː / ; pl. SoCs / ˌ ˈ ɛ s oʊ s iː z / )

1160-500: A 32-bit and a 64-bit architecture: MIPS32 and MIPS64. Both were introduced in 1999. MIPS32 is based on MIPS II with some additional features from MIPS III, MIPS IV, and MIPS V; MIPS64 is based on MIPS V. NEC , Toshiba and SiByte (later acquired by Broadcom ) each obtained licenses for MIPS64 as soon as it was announced. Philips , LSI Logic , IDT , Raza Microelectronics, Inc. , Cavium , Loongson Technology and Ingenic Semiconductor have since joined them. MIPS32/MIPS64 Release 5

1276-465: A 6-bit opcode. In addition to the opcode, R-type instructions specify three registers, a shift amount field, and a function field; I-type instructions specify two registers and a 16-bit immediate value; J-type instructions follow the opcode with a 26-bit jump target. The following are the three formats used for the core instruction set: MIPS I has instructions that load and store 8-bit bytes, 16-bit halfwords, and 32-bit words. Only one addressing mode

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1392-515: A certain level of computational performance , but power is limited in most SoC environments. SoC designs are optimized to minimize waste heat output on the chip. As with other integrated circuits , heat generated due to high power density are the bottleneck to further miniaturization of components. The power densities of high speed integrated circuits, particularly microprocessors and including SoCs, have become highly uneven. Too much waste heat can damage circuits and erode reliability of

1508-527: A chip consists of both the hardware , described in § Structure , and the software controlling the microcontroller, microprocessor or digital signal processor cores, peripherals and interfaces. The design flow for an SoC aims to develop this hardware and software at the same time, also known as architectural co-design. The design flow must also take into account optimizations ( § Optimization goals ) and constraints. Most SoCs are developed from pre-qualified hardware component IP core specifications for

1624-1005: A circuit is the integral of power consumed with respect to time, and the average rate of power consumption is the product of current by voltage . Equivalently, by Ohm's law , power is current squared times resistance or voltage squared divided by resistance : P = I V = V 2 R = I 2 R {\displaystyle P=IV={\frac {V^{2}}{R}}={I^{2}}{R}} SoCs are frequently embedded in portable devices such as smartphones , GPS navigation devices , digital watches (including smartwatches ) and netbooks . Customers want long battery lives for mobile computing devices, another reason that power consumption must be minimized in SoCs. Multimedia applications are often executed on these devices, including video games, video streaming , image processing ; all of which have grown in computational complexity in recent years with user demands and expectations for higher- quality multimedia. Computation

1740-552: A corresponding microMIPS32/64 version. A processor may implement microMIPS32/64 or both microMIPS32/64 and its corresponding MIPS32/64 subset. Starting with MIPS32/64 Release 6, support for MIPS16e ended, and microMIPS is the only form of code compression in MIPS. The base MIPS32 and MIPS64 architectures can be supplemented with a number of optional architectural extensions, which are collectively referred to as application-specific extensions (ASEs). These ASEs provide features that improve

1856-866: A different processor. For further discussion of multi-processing memory issues, see cache coherence and memory latency . SoCs include external interfaces , typically for communication protocols . These are often based upon industry standards such as USB , Ethernet , USART , SPI , HDMI , I²C , CSI , etc. These interfaces will differ according to the intended application. Wireless networking protocols such as Wi-Fi , Bluetooth , 6LoWPAN and near-field communication may also be supported. When needed, SoCs include analog interfaces including analog-to-digital and digital-to-analog converters , often for signal processing . These may be able to interface with different types of sensors or actuators , including smart transducers . They may interface with application-specific modules or shields. Or they may be internal to

1972-439: A discrete application processor). High-performance SoCs are often paired with dedicated and physically separate memory and secondary storage (such as LPDDR and eUFS or eMMC , respectively) chips that may be layered on top of the SoC in what is known as a package on package (PoP) configuration, or be placed close to the SoC. Additionally, SoCs may use separate wireless modems (especially WWAN modems). An SoC integrates

2088-621: A four-port network switch, and support for Wi-Fi 802.11b/g. After Linksys was obliged to release source code of the WRT54G's firmware under terms of the GNU General Public License , there have been many third party projects enhancing that code as well as some entirely new projects using the hardware in these devices. Three of the most widely used are DD-WRT , Tomato and OpenWrt . As of January 2006, most third-party firmware are no longer compatible with version 5 of both

2204-521: A hardware layer-2 load balancer (with appropriate third party firmware). Linksys released the WRT54GL (the best-selling router of all time) in 2005 to support third-party firmware based on Linux , after the original WRT54G line was switched from Linux to VxWorks , starting with version 5. The WRT54GL is technically a reissue of the version 4 WRT54G. Cisco was sued by the FSF for copyright infringement, but

2320-464: A manner independent of time scales, which are typically specified in HDL. Other components can remain software and be compiled and embedded onto soft-core processors included in the SoC as modules in HDL as IP cores . Once the architecture of the SoC has been defined, any new hardware elements are written in an abstract hardware description language termed register transfer level (RTL) which defines

2436-466: A new data type, the Paired Single (PS), which consisted of two single-precision (32-bit) floating-point numbers stored in the existing 64-bit floating-point registers. Variants of existing floating-point instructions for arithmetic, compare and conditional move were added to operate on this data type in a SIMD fashion. New instructions were added for loading, rearranging and converting PS data. It

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2552-415: A pair of 32-bit registers called HI and LO, since they may execute separately from (and concurrently with) the other CPU instructions. For multiplication, the high- and low-order halves of the 64-bit product is written to HI and LO (respectively). For division, the quotient is written to LO and the remainder to HI. To access the results, a pair of instructions (Move from HI and Move from LO) is provided to copy

2668-486: A power source while needing to maintain autonomous function, and often are limited in power use by a high number of embedded SoCs being networked together in an area. Additionally, energy costs can be high and conserving energy will reduce the total cost of ownership of the SoC. Finally, waste heat from high energy consumption can damage other circuit components if too much heat is dissipated, giving another pragmatic reason to conserve energy. The amount of energy used in

2784-464: A smaller semiconductor die area. This comes at the cost of reduced replaceability of components. By definition, SoC designs are fully or nearly fully integrated across different component modules . For these reasons, there has been a general trend towards tighter integration of components in the computer hardware industry , in part due to the influence of SoCs and lessons learned from the mobile and embedded computing markets. SoCs are very common in

2900-495: A software integrated development environment . SoCs components are also often designed in high-level programming languages such as C++ , MATLAB or SystemC and converted to RTL designs through high-level synthesis (HLS) tools such as C to HDL or flow to HDL . HLS products called "algorithmic synthesis" allow designers to use C++ to model and synthesize system, circuit, software and verification levels all in one high level language commonly known to computer engineers in

3016-429: A specific type of workload. Multiprocessor SoCs have more than one processor core by definition. The ARM architecture is a common choice for SoC processor cores because some ARM-architecture cores are soft processors specified as IP cores . SoCs must have semiconductor memory blocks to perform their computation, as do microcontrollers and other embedded systems . Depending on the application, SoC memory may form

3132-399: A version 5 WRT54G. An easier method not requiring any disassembly of the device has since been devised for flashing v5-v8 to DD-WRT. MIPS architecture MIPS ( Microprocessor without Interlocked Pipelined Stages ) is a family of reduced instruction set computer (RISC) instruction set architectures (ISA) developed by MIPS Computer Systems, now MIPS Technologies , based in

3248-410: Is a 64-bit version of the original shift instructions, used to specify constant shift distances of 0–31 bits. The second version is similar to the first, but adds 32 10 the shift amount field's value so that constant shift distances of 32–63 bits can be specified. The third version obtains the shift distance from the six low-order bits of a GPR. MIPS III added a supervisor privilege level in between

3364-460: Is a confusingly named derivative of the WRT54G. It is a compact wireless travel router with SpeedBooster support that has only one LAN and one WAN Fast Ethernet interfaces, but has two wireless interfaces. The WTR54GS has the ability to make an unencrypted wireless connection on one interface, and make open shared connections on the other wireless interface, or the LAN port. The WRT54G2 is an iteration of

3480-554: Is also called the Rogers TalkSpot Voice-Optimized Router. It works with Rogers' Talkspot UMA service, which allows calls to be made via Rogers' cellular network or via Wi-Fi Unlicensed Mobile Access (UMA), using the same telephone and phone number. A UMA-compatible phone is required. The WRT54G-RG and the WRT54G-TM are identical in terms of hardware. The WRT54GH comes with an internal antenna,

3596-578: Is an integrated circuit that integrates most or all components of a computer or electronic system . These components usually include an on-chip central processing unit (CPU), memory interfaces, input/output devices and interfaces, and secondary storage interfaces, often alongside other components such as radio modems and a graphics processing unit (GPU) – all on a single substrate or microchip. SoCs may contain digital and also analog , mixed-signal and often radio frequency signal processing functions (otherwise it may be considered on

Linksys WRT54G series - Misplaced Pages Continue

3712-574: Is an exception and has an internal antenna with optional external antenna. As a cost-cutting measure, as well as to satisfy FCC rules that prohibit fitting external antennas with higher gain, the design of the latest version of the WRT54G no longer has detachable antennas or TNC connectors. Instead, version 8 routers simply route thin wires into antenna 'shells' eliminating the connector. As a result, Linksys HGA7T and similar external antennas are no longer compatible with this model. Until version 5, WRT54G shipped with Linux -based firmware . Note: some of

3828-539: Is denoted by the .d suffix. MIPS II removed the load delay slot and added several sets of instructions. For shared-memory multiprocessing, the Synchronize Shared Memory , Load Linked Word , and Store Conditional Word instructions were added. A set of Trap-on-Condition instructions were added. These instructions caused an exception if the evaluated condition is true. All existing branch instructions were given branch-likely versions that executed

3944-438: Is implementation-defined), to exceed or meet IEEE 754 accuracy requirements (respectively). The FP reciprocal and reciprocal square-root instructions do not comply with IEEE 754 accuracy requirements, and produce results that differ from the required accuracy by one or two units of last place (it is implementation defined). These instructions serve applications where instruction latency is more important than accuracy. MIPS V added

4060-492: Is more demanding as expectations move towards 3D video at high resolution with multiple standards , so SoCs performing multimedia tasks must be computationally capable platform while being low power to run off a standard mobile battery. SoCs are optimized to maximize power efficiency in performance per watt: maximize the performance of the SoC given a budget of power usage. Many applications such as edge computing , distributed processing and ambient intelligence require

4176-780: Is necessarily a design goal of SoCs. If optimization was not necessary, the engineers would use a multi-chip module architecture without accounting for the area use, power consumption or performance of the system to the same extent. Common optimization targets for SoC designs follow, with explanations of each. In general, optimizing any of these quantities may be a hard combinatorial optimization problem, and can indeed be NP-hard fairly easily. Therefore, sophisticated optimization algorithms are often required and it may be practical to use approximation algorithms or heuristics in some cases. Additionally, most SoC designs contain multiple variables to optimize simultaneously , so Pareto efficient solutions are sought after in SoC design. Oftentimes

4292-472: Is only defined for 32-bit MIPS, but GCC has created a 64-bit variation called O64. For 64-bit, the N64 ABI by Silicon Graphics is most commonly used. The most important improvement is that eight registers are now available for argument passing; it also increases the number of floating-point registers to 32. There is also an ILP32 version called N32, which uses 32-bit pointers for smaller code, analogous to

4408-592: Is shipping in, amongst other countries, the United Kingdom. This unit has 1 MB flash, 4 MB RAM and a non-detachable external antenna. The internal hardware is based on a Marvell ARM914 ("Libertas") reference design which is probably identical to the SerComm IP806SM, Xterasys XR-2407G, Abocom ARM914, Hawking HWGR54 Revision M, and the Airlink 101 AR315W. By appropriately changing the value of

4524-428: Is supported: base + displacement. Since MIPS I is a 32-bit architecture, loading quantities fewer than 32 bits requires the datum to be either sign-extended or zero-extended to 32 bits. The load instructions suffixed by "unsigned" perform zero extension; otherwise sign extension is performed. Load instructions source the base from the contents of a GPR (rs) and write the result to another GPR (rt). Store instructions source

4640-642: Is the link register . For integer multiplication and division instructions, which run asynchronously from other instructions, a pair of 32-bit registers, HI and LO , are provided. There is a small set of instructions for copying data between the general-purpose registers and the HI/LO registers. The program counter has 32 bits. The two low-order bits always contain zero since MIPS I instructions are 32 bits long and are aligned to their natural word boundaries. Instructions are divided into three types: R (register), I (immediate), and J (jump). Every instruction starts with

4756-683: Is the System Control Coprocessor (an essential part of the processor that is implementation-defined in MIPS I–V), CP1 is an optional floating-point unit (FPU) and CP2/3 are optional implementation-defined coprocessors (MIPS III removed CP3 and reused its opcodes for other purposes). For example, in the PlayStation video game console, CP2 is the Geometry Transformation Engine (GTE), which accelerates

Linksys WRT54G series - Misplaced Pages Continue

4872-656: The Advanced Computing Environment (ACE) consortium to advance its Advanced RISC Computing (ARC) standard, which aimed to establish MIPS as the dominant personal computing platform. ARC found little success in personal computers, but the R4000 (and the R4400 derivative) were widely used in workstation and server computers, especially by its largest user, Silicon Graphics . Other uses of the R4000 included high-end embedded systems and supercomputers. MIPS III

4988-545: The PlayStation , were among the highest volume users of MIPS architecture processors in the mid-1990s. The first MIPS IV implementation was the MIPS Technologies R8000 microprocessor chipset (1994). The design of the R8000 began at Silicon Graphics, Inc. and it was only used in high-end workstations and servers for scientific and technical applications where high performance on large floating-point workloads

5104-524: The United States . There are multiple versions of MIPS, including MIPS I, II, III, IV, and V, as well as five releases of MIPS32/64 (for 32- and 64-bit implementations, respectively). The early MIPS architectures were 32-bit; 64-bit versions were developed later. As of April 2017, the current version of MIPS is MIPS32/64 Release 6. MIPS32/64 primarily differs from MIPS I–V by defining the privileged kernel mode System Control Coprocessor in addition to

5220-895: The bottlenecks of bus-based networks. Networks-on-chip have advantages including destination- and application-specific routing , greater power efficiency and reduced possibility of bus contention . Network-on-chip architectures take inspiration from communication protocols like TCP and the Internet protocol suite for on-chip communication, although they typically have fewer network layers . Optimal network-on-chip network architectures are an ongoing area of much research interest. NoC architectures range from traditional distributed computing network topologies such as torus , hypercube , meshes and tree networks to genetic algorithm scheduling to randomized algorithms such as random walks with branching and randomized time to live (TTL). Many SoC researchers consider NoC architectures to be

5336-529: The mobile computing (as in smart devices such as smartphones and tablet computers ) and edge computing markets. In general, there are three distinguishable types of SoCs: SoCs can be applied to any computing task. However, they are typically used in mobile computing such as tablets, smartphones, smartwatches, and netbooks as well as embedded systems and in applications where previously microcontrollers would be used. Where previously only microcontrollers could be used, SoCs are rising to prominence in

5452-554: The x32 ABI . Both run under the 64-bit mode of the CPU. The N32 and N64 ABIs pass the first eight arguments to a function in the registers $ a0 - $ a7 ; subsequent arguments are passed on the stack. The return value (or a pointer to it) is stored in the registers $ v0 ; a second return value may be stored in $ v1 . In both the N32 and N64 ABIs all registers are considered to be 64-bits wide. A few attempts have been made to replace O32 with

5568-408: The 32-bit sign-extended result to the sum of the program counter (instruction address) and 8 10 . Jumps have two versions: absolute and register-indirect. Absolute jumps ("Jump" and "Jump and Link") compute the address to which control is transferred by shifting the 26-bit instr_index left by two bits and concatenating the 28-bit result with the four high-order bits of the address of the instruction in

5684-449: The CPU and FPU convert single- and double-precision floating-point numbers into doubleword integers and vice versa. MIPS IV is the fourth version of the architecture. It is a superset of MIPS III and is compatible with all existing versions of MIPS. MIPS IV was designed to mainly improve floating-point (FP) performance. To improve access to operands, an indexed addressing mode (base + index, both sourced from GPRs) for FP loads and stores

5800-492: The FPGA RTL that make signals available for observation. This is used to debug hardware, firmware and software interactions across multiple FPGAs with capabilities similar to a logic analyzer. In parallel, the hardware elements are grouped and passed through a process of logic synthesis , during which performance constraints, such as operational frequency and expected signal delays, are applied. This generates an output known as

5916-533: The GPRs and HI/LO registers. For shared-memory multiprocessing, the Load Linked Double Word , and Store Conditional Double Word instructions were added. Existing instructions originally defined to operate on 32-bit words were redefined, where necessary, to sign-extend the 32-bit results to permit words and doublewords to be treated identically by most instructions. Among those instructions redefined

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6032-509: The MIPS architecture has ceased. The company has joined the RISC-V foundation and future processor designs will be based on the RISC-V architecture. In spite of this, some licensees such as Loongson continue with new extension of MIPS-compatible ISAs on their own. In January 2024, Loongson won a case over rights to use MIPS architecture. MIPS is a modular architecture supporting up to four coprocessors (CP0/1/2/3). In MIPS terminology, CP0

6148-403: The MIPS architecture. The architecture greatly influenced later RISC architectures such as Alpha . In March 2021, MIPS announced that the development of the MIPS architecture had ended as the company is making the transition to RISC-V . The first version of the MIPS architecture was designed by MIPS Computer Systems for its R2000 microprocessor, the first MIPS implementation. Both MIPS and

6264-502: The MIPS16e ASE. A disadvantage of MIPS16e is that it requires a mode switch before any of its 16-bit instructions can be processed. microMIPS adds versions of the most-frequently used 32-bit instructions that are encoded as 16-bit instructions. This allows programs to intermix 16- and 32-bit instructions without having to switch modes. microMIPS was introduced alongside of MIPS32/64 Release 3, and each subsequent release of MIPS32/64 has

6380-519: The MIPS32 and MIPS64 specifications, as were cache control instructions . For the purpose of cache control, both SYNC and SYNCI instructions were prepared. MIPS32/MIPS64 Release 6 in 2014 added the following: Removed infrequently used instructions: Reorganized the instruction encoding, freeing space for future expansions. The microMIPS32/64 architectures are supersets of the MIPS32 and MIPS64 architectures (respectively) designed to replace

6496-584: The Or Immediate instruction to load a 32-bit immediate into a register. MIPS I has instructions to perform left and right logical shifts and right arithmetic shifts. The operand is obtained from a GPR (rt), and the result is written to another GPR (rd). The shift distance is obtained from either a GPR (rs) or a 5-bit "shift amount" (the "sa" field). MIPS I has instructions for signed and unsigned integer multiplication and division. These instructions source their operands from two GPRs and write their results to

6612-581: The R2000 were introduced together in 1985. When MIPS II was introduced, MIPS was renamed MIPS I to distinguish it from the new version. MIPS Computer Systems ' R6000 microprocessor (1989) was the first MIPS II implementation. Designed for servers, the R6000 was fabricated and sold by Bipolar Integrated Technology , but was a commercial failure. During the mid-1990s, many new 32-bit MIPS processors for embedded systems were MIPS II implementations because

6728-816: The R5000 from Toshiba, the R5900, was used in Sony Computer Entertainment's Emotion Engine , which powered its PlayStation 2 game console. Announced on October 21, 1996, at the Microprocessor Forum 1996 alongside the MIPS Digital Media Extensions (MDMX) extension, MIPS V was designed to improve the performance of 3D graphics transformations. In the mid-1990s, a major use of non-embedded MIPS microprocessors were graphics workstations from Silicon Graphics. MIPS V

6844-737: The SoC, if needed. Popular time sources are crystal oscillators and phase-locked loops . SoC peripherals including counter -timers, real-time timers and power-on reset generators. SoCs also include voltage regulators and power management circuits. SoCs comprise many execution units . These units must often send data and instructions back and forth. Because of this, all but the most trivial SoCs require communications subsystems . Originally, as with other microcomputer technologies, data bus architectures were used, but recently designs based on sparse intercommunication networks known as networks-on-chip (NoC) have risen to prominence and are forecast to overtake bus architectures for SoC design in

6960-1228: The SoC, such as if an analog sensor is built in to the SoC and its readings must be converted to digital signals for mathematical processing. Digital signal processor (DSP) cores are often included on SoCs. They perform signal processing operations in SoCs for sensors , actuators , data collection , data analysis and multimedia processing. DSP cores typically feature very long instruction word (VLIW) and single instruction, multiple data (SIMD) instruction set architectures , and are therefore highly amenable to exploiting instruction-level parallelism through parallel processing and superscalar execution . SP cores most often feature application-specific instructions, and as such are typically application-specific instruction set processors (ASIP). Such application-specific instructions correspond to dedicated hardware functional units that compute those instructions. Typical DSP instructions include multiply-accumulate , Fast Fourier transform , fused multiply-add , and convolutions . As with other computer systems, SoCs require timing sources to generate clock signals , control execution of SoC functions and provide time context to signal processing applications of

7076-519: The WRT54G and the WRT54GS. The amount of flash memory in the version 5 devices has been reduced to 2 MB, too small for current Linux-based third-party firmware. (See table above for information on identifying the version based on the serial number printed on the bottom of the unit, and on the outside of the shrink-wrapped retail box.) Some users have succeeded in flashing and running a stripped down but fully functional version of DD-WRT called 'micro' on

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7192-615: The WRT54G in a smaller, curved black case with internal antenna(s). This unit includes a four port 10/100 switch and one WAN port. 3rd-party firmware: Fully compatible with DD-WRT (micro, micro-plus, and micro-plus with SSH editions). Not compatible with Tomato and other third-party firmware solutions at this time. Firmware: VxWorks FCC ID: Q87-WRT54G2V1 FCC ID: Q87-WRT54G2V11 3rd-party firmware: Supported by DD-WRT. 3rd-party firmware: Supported by DD-WRT. Firmware: VxWorks 5.5 FCC ID: Q87-WRT54G2V13 3rd-party firmware: Not possible with DD-WRT. FCC ID: Q87-WRT54G2V15 * Note: 1.5 of

7308-630: The WRT54G2 is NOT supported by dd-wrt . This is because it uses Atheros components (i.e. the Atheros SoC ) which require more than the 2 MB of Flash Memory built-in for a dd-wrt solution. The WRT54GS2 is the WRT54G2 hardware with the VxWorks 5.5 Firmware including SpeedBooster. It has a sleek black design with 2 internal antennas. It includes a 4-port 10/100 switch and one 10/100 WAN port on

7424-478: The base from the contents of a GPR (rs) and the store data from another GPR (rt). All load and store instructions compute the memory address by summing the base with the sign-extended 16-bit immediate. MIPS I requires all memory accesses to be aligned to their natural word boundaries, otherwise an exception is signaled. To support efficient unaligned memory accesses, there are load/store word instructions suffixed by "left" or "right". All load instructions are followed by

7540-477: The branch delay slot. Register-indirect jumps transfer control to the instruction at the address sourced from a GPR (rs). The address sourced from the GPR must be word-aligned, else an exception is signaled after the instruction in the branch delay slot is executed. Branch and jump instructions that link (except for "Jump and Link Register") save the return address to GPR 31. The "Jump and Link Register" instruction permits

7656-409: The callee needs to save its arguments, but the registers are not stored there by the caller. The return value is stored in register $ v0 ; a second return value may be stored in $ v1 . The ABI took shape in 1990 and was last updated in 1994. This perceived slowness, along with an antique floating-point model with only 16 registers, has encouraged the proliferation of many other calling conventions. It

7772-534: The case was settled. WRTSL54GS is similar to the WRT54GS while adding additional firmware features and a USB 2.0 port (referred to as StorageLink) which can be used for a USB hard disk or flash drive. Unlike other models, the WRTSL54GS has only a single 1.5 dBi antenna, and it is not removable. WRT54GX comes with SRX (Speed and Range eXpansion), which uses "True MIMO " technology. It has three antennas and

7888-427: The circuit behavior, or synthesized into RTL from a high level language through high-level synthesis. These elements are connected together in a hardware description language to create the full SoC design. The logic specified to connect these components and convert between possibly different interfaces provided by different vendors is called glue logic . Chips are verified for validation correctness before being sent to

8004-435: The circuit over time. High temperatures and thermal stress negatively impact reliability, stress migration , decreased mean time between failures , electromigration , wire bonding , metastability and other performance degradation of the SoC over time. In particular, most SoCs are in a small physical area or volume and therefore the effects of waste heat are compounded because there is little room for it to diffuse out of

8120-530: The contents of HI or LO to a GPR. These instructions are interlocked: reads of HI and LO do not proceed past an unfinished arithmetic instruction that will write to HI and LO. Another pair of instructions (Move to HI or Move to LO) copies the contents of a GPR to HI and LO. These instructions are used to restore HI and LO to their original state after exception handling. Instructions that read HI or LO must be separated by two instructions that do not write to HI or LO. All MIPS I control flow instructions are followed by

8236-532: The data throughput of the SoC. This is similar to some device drivers of peripherals on component-based multi-chip module PC architectures. Wire delay is not scalable due to continued miniaturization , system performance does not scale with the number of cores attached, the SoC's operating frequency must decrease with each additional core attached for power to be sustainable, and long wires consume large amounts of electrical power. These challenges are prohibitive to supporting manycore systems on chip. In

8352-676: The designer. Traditionally, engineers have employed simulation acceleration, emulation or prototyping on reprogrammable hardware to verify and debug hardware and software for SoC designs prior to the finalization of the design, known as tape-out . Field-programmable gate arrays (FPGAs) are favored for prototyping SoCs because FPGA prototypes are reprogrammable, allow debugging and are more flexible than application-specific integrated circuits (ASICs). With high capacity and fast compilation time, simulation acceleration and emulation are powerful technologies that provide wide visibility into systems. Both technologies, however, operate slowly, on

8468-415: The efficiency and performance of certain workloads, such as digital signal processing . MIPS has had several calling conventions, especially on the 32-bit platform. The O32 ABI is the most commonly-used ABI, owing to its status as the original System V ABI for MIPS. It is strictly stack-based, with only four registers $ a0 - $ a3 available to pass arguments. Space on the stack is reserved in case

8584-804: The embedded systems market. Tighter system integration offers better reliability and mean time between failure , and SoCs offer more advanced functionality and computing power than microcontrollers. Applications include AI acceleration , embedded machine vision , data collection , telemetry , vector processing and ambient intelligence . Often embedded SoCs target the internet of things , multimedia, networking, telecommunications and edge computing markets. Some examples of SoCs for embedded applications include: Mobile computing based SoCs always bundle processors, memories, on-chip caches , wireless networking capabilities and often digital camera hardware and firmware. With increasing memory sizes, high end SoCs will often have no memory and flash storage and instead,

8700-726: The exact supported aircard. For example, Telus Mobility (CANADA) uses the Sierra Wireless Aircard 595, which is supported by this router, but because it is from Telus Mobility and not from Sprint (USA), it will never load the card into the router to make it operational. This is only true for the Sprint and AT&T-branded models. The WRT54G-TM (TM stands for T-Mobile ) is also called the T-Mobile " Hotspot@Home " service. It allows calls to be made via T-Mobile's GSM network or via Wi-Fi Unlicensed Mobile Access (UMA), using

8816-411: The exception handler. MIPS has 32 floating-point registers. Two registers are paired for double precision numbers. Odd numbered registers cannot be used for arithmetic or branching, just as part of a double precision register pair, resulting in 16 usable registers for most instructions (moves/copies and loads/stores were not affected). Single precision is denoted by the .s suffix, while double precision

8932-505: The existing kernel and user privilege levels. This feature only affected the implementation-defined System Control Processor (Coprocessor 0). MIPS III removed the Coprocessor 3 (CP3) support instructions, and reused its opcodes for the new doubleword instructions. The remaining coprocessors gained instructions to move doublewords between coprocessor registers and the GPRs. The floating general registers (FGRs) were extended to 64 bits and

9048-830: The firmware byte 0x26, the WRT54GC can be cross-flashed with firmware based on the same reference platform. There were reports in 2006 that a sister platform of the WRT54GC (the AR315W) was hacked to run Linux. The WRT54G3G/WRT54G3GV2 Mobile Broadband routers are variants that have four Fast Ethernet ports, one Internet wired port (For DSL/Cable connections), plus a PCMCIA slot for use with a Cellular Based PC Card "aircard". The V2 model has two additional USB ports for 3G modem use and one other USB port, which has yet to be put to use. To use this router with other cellular providers, one must use an alternative firmware. The stock firmware does not support cellular providers, even though one does have

9164-480: The floating point coprocessor also had several instructions added to it. An IEEE 754-compliant floating-point square root instruction was added. It supported both single- and double-precision operands. A set of instructions that converted single- and double-precision floating-point numbers to 32-bit words were added. These complemented the existing conversion instructions by allowing the IEEE rounding mode to be specified by

9280-425: The future of SoC design because they have been shown to efficiently meet power and throughput needs of SoC designs. Current NoC architectures are two-dimensional. 2D IC design has limited floorplanning choices as the number of cores in SoCs increase, so as three-dimensional integrated circuits (3DICs) emerge, SoC designers are looking towards building three-dimensional on-chip networks known as 3DNoCs. A system on

9396-512: The goals of optimizing some of these quantities are directly at odds, further adding complexity to design optimization of SoCs and introducing trade-offs in system design. For broader coverage of trade-offs and requirements analysis , see requirements engineering . SoCs are optimized to minimize the electrical power used to perform the SoC's functions. Most SoCs must use low power. SoC systems often require long battery life (such as smartphones ), can potentially spend months or years without

9512-431: The hardware elements and execution units , collectively "blocks", described above, together with software device drivers that may control their operation. Of particular importance are the protocol stacks that drive industry-standard interfaces like USB . The hardware blocks are put together using computer-aided design tools, specifically electronic design automation tools; the software modules are integrated using

9628-402: The instruction in the branch delay slot only if the branch is taken. These instructions improve performance in certain cases by allowing useful instructions to fill the branch delay slot. Doubleword load and store instructions for COP1–3 were added. Consistent with other memory access instructions, these loads and stores required the doubleword to be naturally aligned. The instruction set for

9744-632: The instruction instead of the Floating Point Control and Status Register. MIPS III is a backwards-compatible extension of MIPS II that added support for 64-bit memory addressing and integer operations. The 64-bit data type is called a doubleword, and MIPS III extended the general-purpose registers, HI/LO registers, and program counter to 64 bits to support it. New instructions were added to load and store doublewords, to perform integer addition, subtraction, multiplication, division, and shift operations on them, and to move doubleword between

9860-409: The introduction of the 64-bit MIPS III architecture in 1991 left MIPS II as the newest 32-bit MIPS architecture until MIPS32 was introduced in 1999. MIPS Computer Systems ' R4000 microprocessor (1991) was the first MIPS III implementation. It was designed for use in personal, workstation, and server computers. MIPS Computer Systems aggressively promoted the MIPS architecture and R4000, establishing

9976-482: The late 2010s, a trend of SoCs implementing communications subsystems in terms of a network-like topology instead of bus-based protocols has emerged. A trend towards more processor cores on SoCs has caused on-chip communication efficiency to become one of the key factors in determining the overall system performance and cost. This has led to the emergence of interconnection networks with router -based packet switching known as " networks on chip " (NoCs) to overcome

10092-598: The memory and flash memory will be placed right next to, or above ( package on package ), the SoC. Some examples of mobile computing SoCs include: In 1992, Acorn Computers produced the A3010, A3020 and A4000 range of personal computers with the ARM250 SoC. It combined the original Acorn ARM2 processor with a memory controller (MEMC), video controller (VIDC), and I/O controller (IOC). In previous Acorn ARM -powered computers, these were four discrete chips. The ARM7500 chip

10208-412: The most recent versions of both the 32-bit and 64-bit designs making them available without any licensing or royalty fees as well as granting participants licenses to existing MIPS patents. In March 2019, one version of the architecture was made available under a royalty-free license, but later that year the program was shut down again. In March 2021, Wave Computing announced that the development of

10324-425: The near future. Historically, a shared global computer bus typically connected the different components, also called "blocks" of the SoC. A very common bus for SoC communications is ARM's royalty-free Advanced Microcontroller Bus Architecture ( AMBA ) standard. Direct memory access controllers route data directly between external interfaces and SoC memory, bypassing the CPU or control unit , thereby increasing

10440-430: The order of MHz, which may be significantly slower – up to 100 times slower – than the SoC's operating frequency. Acceleration and emulation boxes are also very large and expensive at over US$ 1 million. FPGA prototypes, in contrast, use FPGAs directly to enable engineers to validate and test at, or close to, a system's full operating frequency with real-world stimuli. Tools such as Certus are used to insert probes in

10556-398: The processing of geometry in 3D computer graphics. MIPS is a load/store architecture (also known as a register-register architecture ); except for the load/store instructions used to access memory , all instructions operate on the registers. MIPS I has thirty-two 32-bit general-purpose registers (GPR). Register $ 0 is hardwired to zero and writes to it are discarded. Register $ 31

10672-501: The rear. FCC ID:Q87-WRT54G2V1 WRT54GC series with 802.11b/g support. This unit has a four port 10/100 switch and one WAN port. The "C" in the router number stands for compact, as the unit measures 4" by 4" by 1" with an internal antenna. The unit can be expanded with addition of HGA7S external antenna to boost range. Hardware Version 1.0 is the only option available in the United States since introduction in 2005. Version 2.0

10788-507: The requirement for instructions to use even-numbered register only was removed. This is incompatible with earlier versions of the architecture; a bit in the floating-point control/status register is used to operate the MIPS III floating-point unit (FPU) in a MIPS I- and II-compatible mode. The floating-point control registers were not extended for compatibility. The only new floating-point instructions added were those to copy doublewords between

10904-562: The result to a third GPR (rd). Alternatively, addition can source one of the operands from a 16-bit immediate (which is sign-extended to 32 bits). The instructions for addition and subtraction have two variants: by default, an exception is signaled if the result overflows; instructions with the "unsigned" suffix do not signal an exception. The overflow check interprets the result as a 32-bit two's complement integer. MIPS I has instructions to perform bitwise logical AND, OR, XOR, and NOR. These instructions source their operands from two GPRs and write

11020-413: The result to a third GPR. By default, the operands are interpreted as signed integers. The variants of these instructions that are suffixed with "unsigned" interpret the operands as unsigned integers (even those that source an operand from the sign-extended 16-bit immediate). The Load Immediate Upper instruction copies the 16-bit immediate into the high-order 16 bits of a GPR. It is used in conjunction with

11136-427: The result to a third GPR. The AND, OR, and XOR instructions can alternatively source one of the operands from a 16-bit immediate (which is zero-extended to 32 bits). The Set on relation instructions write one or zero to the destination register if the specified relation is true or false. These instructions source their operands from two GPRs or one GPR and a 16-bit immediate (which is sign-extended to 32 bits), and write

11252-410: The return address to be saved to any writable GPR. MIPS I has two instructions for software to signal an exception: System Call and Breakpoint. System Call is used by user mode software to make kernel calls; and Breakpoint is used to transfer control to a debugger via the kernel's exception handler. Both instructions have a 20-bit Code field that can contain operating environment-specific information for

11368-633: The risk of catastrophic failure . Due to increased transistor densities as length scales get smaller, each process generation produces more heat output than the last. Compounding this problem, SoC architectures are usually heterogeneous, creating spatially inhomogeneous heat fluxes , which cannot be effectively mitigated by uniform passive cooling . SoCs are optimized to maximize computational and communications throughput . SoCs are optimized to minimize latency for some or all of their functions. This can be accomplished by laying out elements with proper proximity and locality to each-other to minimize

11484-546: The routers have BCM4702 CPU The WRT54GS is nearly identical to the WRT54G except for additional RAM, flash memory, and SpeedBooster software. Versions 1 to 3 of this router have 8 MB of flash memory. Since most third parties' firmware only use up to 4 MB flash, a JFFS2 -based read/write filesystem can be created and used on the remaining 4 MB free flash. This allows for greater flexibility of configurations and scripting, enabling this small router to both load-balance multiple ADSL lines (multi-homed) or to be run as

11600-431: The same telephone and phone number (a special dual-mode phone designed for the service is required e.g. BlackBerry Pearl 8120 ). Additionally, once a call is in progress, one may transition from Wi-Fi to GSM (and vice versa) seamlessly, as Wi-Fi signal comes and goes, such as when entering or exiting a home or business. A special router is not needed to use the service, but the T-Mobile branded routers are supposed to enhance

11716-458: The slower but cheaper dynamic RAM (DRAM). When an SoC has a cache hierarchy, SRAM will usually be used to implement processor registers and cores' built-in caches whereas DRAM will be used for main memory . "Main memory" may be specific to a single processor (which can be multi-core ) when the SoC has multiple processors , in this case it is distributed memory and must be sent via § Intermodule communication on-chip to be accessed by

11832-516: The speed and 2 times the range over standard 802.11g routers. Chipset Realtek. It is not compatible with DD-WRT . WRT54GX4 has 3 moveable antennas, and is advertised to have 10 times the speed and 3 times the range of standard 802.11g routers. WRT54GX4-EU: chipset Realtek RTL8651B, radio chipset Airgo AGN303BB, flash S29GL064M90TFIR4. It does not appear to be compatible with DD-WRT. WRT series with 802.11a support. (First Generation) BCM5325A WRT54G series with 802.11a support. The Linksys WTR54GS

11948-420: The system. Because of high transistor counts on modern devices, oftentimes a layout of sufficient throughput and high transistor density is physically realizable from fabrication processes but would result in unacceptably high amounts of heat in the circuit's volume. These thermal effects force SoC and other chip designers to apply conservative design margins , creating less performant devices to mitigate

12064-533: The telephone's battery life. This is the only known tweak to the TM version of the firmware. The hardware appears similar to that of the WRT54GL, except it has 32 MB RAM and 8 MB flash memory. The WRT54G-TM having a serial number that starts with C061 has these specifications: WRT54G-TM The Tomato Firmware also works on the WRT54G-TM. WRT U 54G-TM WRTU54G V2 -TM The WRT54G-RG (RG stands for Rogers )

12180-747: The total to eight. FP comparison and branch instructions were redefined so they could specify which condition bit was written or read (respectively); and the delay slot in between an FP branch that read the condition bit written to by a prior FP comparison was removed. Support for partial predication was added in the form of conditional move instructions for both GPRs and FPRs; and an implementation could choose between having precise or imprecise exceptions for IEEE 754 traps. MIPS IV added several new FP arithmetic instructions for both single- and double-precision FPNs: fused-multiply add or subtract, reciprocal, and reciprocal square-root. The FP fused-multiply add or subtract instructions perform either one or two roundings (it

12296-520: The user mode architecture. The MIPS architecture has several optional extensions: MIPS-3D , a simple set of floating-point SIMD instructions dedicated to common 3D tasks; MDMX (MaDMaX), a more extensive integer SIMD instruction set using 64-bit floating-point registers; MIPS16e, which adds compression to the instruction stream to reduce the space programs take up; and MIPS MT, which adds multithreading capability. Computer architecture courses in universities and technical schools often study

12412-414: Was Load Word . In MIPS III it sign-extends words to 64 bits. To complement Load Word , a version that zero-extends was added. The R instruction format's inability to specify the full shift distance for 64-bit shifts (its 5-bit shift amount field is too narrow to specify the shift distance for doublewords) required MIPS III to provide three 64-bit versions of each MIPS I shift instruction. The first version

12528-411: Was added, as were prefetch instructions for performing memory prefetching and specifying cache hints (these supported both the base + offset and base + index addressing modes). MIPS IV added several features to improve instruction-level parallelism. To alleviate the bottleneck caused by a single condition bit, seven condition code bits were added to the floating-point control and status register, bringing

12644-538: Was announced on December 6, 2012. According to the Product Marketing Director at MIPS, Release 4 was skipped because the number four is perceived as unlucky in many Asian cultures. In December 2018, Wave Computing, the new owner of the MIPS architecture, announced that MIPS ISA would be open-sourced in a program dubbed the MIPS Open initiative. The program was intended to open up access to

12760-407: Was based on MIPS V and retains all of its features as an optional Coprocessor 1 (FPU) feature called Paired-Single. When MIPS Technologies was spun-out of Silicon Graphics in 1998, it refocused on the embedded market. Through MIPS V, each successive version was a strict superset of the previous version, but this property was found to be a problem, and the architecture definition was changed to define

12876-600: Was completed by the integer-only MDMX extension to provide a complete system for improving the performance of 3D graphics applications. MIPS V implementations were never introduced. On May 12, 1997, Silicon Graphics announced the H1 ("Beast") and H2 ("Capitan") microprocessors. The former was to have been the first MIPS V implementation, and was due to be introduced in the first half of 1999. The H1 and H2 projects were later combined and eventually canceled in 1998. While there have not been any MIPS V implementations, MIPS64 Release 1 (1999)

12992-552: Was eventually implemented by a number of embedded microprocessors. Quantum Effect Design 's R4600 (1993) and its derivatives was widely used in high-end embedded systems and low-end workstations and servers. MIPS Technologies' R4200 (1994), was designed for embedded systems, laptop, and personal computers. A derivative, the R4300i, fabricated by NEC Electronics , was used in the Nintendo 64 game console. The Nintendo 64, along with

13108-662: Was important. Later implementations were the MIPS Technologies R10000 (1996) and the Quantum Effect Devices R5000 (1996) and RM7000 (1998). The R10000, fabricated and sold by NEC Electronics and Toshiba, and its derivatives were used by NEC, Pyramid Technology, Silicon Graphics, and Tandem Computers (among others) in workstations, servers, and supercomputers. The R5000 and R7000 found use in high-end embedded systems, personal computers, and low-end workstations and servers. A derivative of

13224-427: Was once marketed as a "Pre-N" router, with eight times the speed and three times the range over standard 802.11g routers. WRT54GP2 has 1 or 2 antennas, and a built-in analog telephony adapter (ATA) with 2 phone lines, but only 3 network ports. "Vonage" WRTP54G has 1 antenna, 2 phone lines, 4 network ports — Same S/N Prefix CGZ0 on WRT54GP2 WRT54GX2 has 2 antennas, and was advertised to have up to 6 times

13340-437: Was the first instruction set to exploit floating-point SIMD with existing resources. The first release of MIPS32, based on MIPS II, added conditional moves, prefetch instructions , and other features from the R4000 and R5000 families of 64-bit processors. The first release of MIPS64 adds a MIPS32 mode to run 32-bit code. The MUL and MADD ( multiply-add ) instructions, previously available in some implementations, were added to

13456-713: Was their second-generation SoC, based on the ARM700, VIDC20 and IOMD controllers, and was widely licensed in embedded devices such as set-top-boxes, as well as later Acorn personal computers. Tablet and laptop manufacturers have learned lessons from embedded systems and smartphone markets about reduced power consumption, better performance and reliability from tighter integration of hardware and firmware modules , and LTE and other wireless network communications integrated on chip (integrated network interface controllers ). An SoC consists of hardware functional units , including microprocessors that run software code , as well as

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