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2,201 | Removed infrequently used instructions: |
2,202 | Reorganized the instruction encoding, freeing space for future expansions. |
2,203 | The microMIPS32/64 architectures are supersets of the MIPS32 and MIPS64 architectures designed to replace 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... |
2,204 | 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 . These ASEs provide features that improve the efficiency and performance of certain workloads, such as digital signal processing. |
2,205 | MIPS has had several calling conventions, especially on the 32-bit platform. |
2,206 | 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 the callee needs to save its arguments, but the registers are not stored there by the cal... |
2,207 | 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, analog... |
2,208 | A few attempts have been made to replace O32 with 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 ... |
2,209 | For all of O32 and N32/N64, the return address is stored in a $ra register. This is automatically set with the use of the JAL or JALR instructions. The function prologue of a MIPS subroutine pushes the return address to the stack. |
2,210 | On both O32 and N32/N64 the stack grows downwards, but the N32/N64 ABIs require 64-bit alignment for all stack entries. The frame pointer is optional and in practice rarely used except when the stack allocation in a function is determined at runtime, for example, by calling alloca. |
2,211 | For N32 and N64, the return address is typically stored 8 bytes before the stack pointer although this may be optional. |
2,212 | For the N32 and N64 ABIs, a function must preserve the $s0-$s7 registers, the global pointer , the stack pointer and the frame pointer . The O32 ABI is the same except the calling function is required to save the $gp register instead of the called function. |
2,213 | For multi-threaded code, the thread local storage pointer is typically stored in special hardware register $29 and is accessed by using the mfhw instruction. At least one vendor is known to store this information in the $k0 register which is normally reserved for kernel use, but this is not standard. |
2,214 | The $k0 and $k1 registers are reserved for kernel use and should not be used by applications since these registers can be changed at any time by the kernel due to interrupts, context switches or other events. |
2,215 | Registers that are preserved across a call are registers that will not be changed by a system call or procedure call. For example, $s-registers must be saved to the stack by a procedure that needs to use them, and $sp and $fp are always incremented by constants, and decremented back after the procedure is done with t... |
2,216 | The userspace calling convention of position-independent code on Linux additionally requires that when a function is called the $t9 register must contain the address of that function. This convention dates back to the System V ABI supplement for MIPS. |
2,217 | MIPS processors are used in embedded systems such as residential gateways and routers. Originally, MIPS was designed for general-purpose computing. During the 1980s and 1990s, MIPS processors for personal, workstation, and server computers were used by many companies such as Digital Equipment Corporation, MIPS Computer... |
2,218 | Historically, video game consoles such as the Nintendo 64, Sony PlayStation, PlayStation 2, and PlayStation Portable used MIPS processors. MIPS processors also used to be popular in supercomputers during the 1990s, but all such systems have dropped off the TOP500 list. These uses were complemented by embedded applicati... |
2,219 | In the mid- to late-1990s, it was estimated that one in three RISC microprocessors produced was a MIPS processor. |
2,220 | By the late 2010s, MIPS machines were still commonly used in embedded markets, including automotive, wireless router, LTE modems , and microcontrollers . They have mostly faded out of the personal, server, and application space. |
2,221 | Open Virtual Platforms includes the freely available for non-commercial use simulator OVPsim, a library of models of processors, peripherals and platforms, and APIs which enable users to develop their own models. The models in the library are open source, written in C, and include the MIPS 4K, 24K, 34K, 74K, 1004K, 10... |
2,222 | There is a freely available MIPS32 simulator called SPIM for use in education. EduMIPS64 is a GPL graphical cross-platform MIPS64 CPU simulator, written in Java/Swing. It supports a wide subset of the MIPS64 ISA and allows the user to graphically see what happens in the pipeline when an assembly program is run by the ... |
2,223 | MARS is another GUI-based MIPS emulator designed for use in education, specifically for use with Hennessy's Computer Organization and Design. |
2,224 | WebMIPS is a browser-based MIPS simulator with visual representation of a generic, pipelined processor. This simulator is quite useful for register tracking during step by step execution. |
2,225 | QtMips provides simple 5-stages pipeline visualization as well as cache principle visualization for basic computer architectures courses. Windows, Linux, macOS and online version is available. |
2,226 | More advanced free emulators are available from the GXemul and QEMU projects. These emulate the various MIPS III and IV microprocessors in addition to entire computer systems which use them. |
2,227 | Commercial simulators are available especially for the embedded use of MIPS processors, for example Wind River Simics , Imperas , VaST Systems , and CoWare . |
2,228 | The Creator simulator is portable and allows the user to learn various assembly languages of different processors . |
2,229 | An electronic calculator is typically a portable electronic device used to perform calculations, ranging from basic arithmetic to complex mathematics. |
2,230 | The first solid-state electronic calculator was created in the early 1960s. Pocket-sized devices became available in the 1970s, especially after the Intel 4004, the first microprocessor, was developed by Intel for the Japanese calculator company Busicom. |
2,231 | Modern electronic calculators vary from cheap, give-away, credit-card-sized models to sturdy desktop models with built-in printers. They became popular in the mid-1970s as the incorporation of integrated circuits reduced their size and cost. By the end of that decade, prices had dropped to the point where a basic calcu... |
2,232 | Computer operating systems as far back as early Unix have included interactive calculator programs such as dc and hoc, and interactive BASIC could be used to do calculations on most 1970s and 1980s home computers. Calculator functions are included in most smartphones, tablets and personal digital assistant type device... |
2,233 | In addition to general purpose calculators, there are those designed for specific markets. For example, there are scientific calculators which include trigonometric and statistical calculations. Some calculators even have the ability to do computer algebra. Graphing calculators can be used to graph functions defined on... |
2,234 | With the very wide availability of smartphones and the like, dedicated hardware calculators, while still widely used, are less common than they once were. In 1986, calculators still represented an estimated 41% of the world's general-purpose hardware capacity to compute information. By 2007, this had diminished to les... |
2,235 | Electronic calculators contain a keyboard with buttons for digits and arithmetical operations; some even contain "00" and "000" buttons to make larger or smaller numbers easier to enter. Most basic calculators assign only one digit or operation on each button; however, in more specific calculators, a button can perform... |
2,236 | Calculators usually have liquid-crystal displays as output in place of historical light-emitting diode displays and vacuum fluorescent displays ; details are provided in the section Technical improvements. |
2,237 | Large-sized figures are often used to improve readability; while using decimal separator instead of or in addition to vulgar fractions. Various symbols for function commands may also be shown on the display. Fractions such as 1⁄3 are displayed as decimal approximations, for example rounded to 0.33333333. Also, some fr... |
2,238 | Calculators also have the ability to save numbers into computer memory. Basic calculators usually store only one number at a time; more specific types are able to store many numbers represented in variables. Usually these variables are named ans or ans. The variables can also be used for constructing formulas. Some mod... |
2,239 | Power sources of calculators are batteries, solar cells or mains electricity , turning on with a switch or button. Some models even have no turn-off button but they provide some way to put off . Crank-powered calculators were also common in the early computer era. |
2,240 | The following keys are common to most pocket calculators. While the arrangement of the digits is standard, the positions of other keys vary from model to model; the illustration is an example. |
2,241 | The arrangement of digits on calculator and other numeric keypads with the 7-8-9 keys two rows above the 1-2-3 keys is derived from calculators and cash registers. It is notably different from the layout of telephone Touch-Tone keypads which have the 1-2-3 keys on top and 7-8-9 keys on the third row. |
2,242 | In general, a basic electronic calculator consists of the following components: |
2,243 | Clock rate of a processor chip refers to the frequency at which the central processing unit is running. It is used as an indicator of the processor's speed, and is measured in clock cycles per second or hertz . For basic calculators, the speed can vary from a few hundred hertz to the kilohertz range. |
2,244 | A basic explanation as to how calculations are performed in a simple four-function calculator: |
2,245 | To perform the calculation 25 + 9, one presses keys in the following sequence on most calculators: 2 5 + 9 =. |
2,246 | Other functions are usually performed using repeated additions or subtractions. |
2,247 | Most pocket calculators do all their calculations in binary-coded decimal rather than binary. BCD is common in electronic systems where a numeric value is to be displayed, especially in systems consisting solely of digital logic, and not containing a microprocessor. By employing BCD, the manipulation of numerical dat... |
2,248 | The same argument applies when hardware of this type uses an embedded microcontroller or other small processor. Often, smaller code results when representing numbers internally in BCD format, since a conversion from or to binary representation can be expensive on such limited processors. For these applications, some sm... |
2,249 | Where calculators have added functions , software algorithms are required to produce high precision results. Sometimes significant design effort is needed to fit all the desired functions in the limited memory space available in the calculator chip, with acceptable calculation time. |
2,250 | The first known tools used to aid arithmetic calculations were: bones , pebbles, and counting boards, and the abacus, known to have been used by Sumerians and Egyptians before 2000 BC. Except for the Antikythera mechanism , development of computing tools arrived near the start of the 17th century: the geometric-militar... |
2,251 | The Renaissance saw the invention of the mechanical calculator by Wilhelm Schickard in 1623, and later by Blaise Pascal in 1642. A device that was at times somewhat over-promoted as being able to perform all four arithmetic operations with minimal human intervention. Pascal's calculator could add and subtract two numbe... |
2,252 | The 18th century saw the arrival of some notable improvements, first by Poleni with the first fully functional calculating clock and four-operation machine, but these machines were almost always one of a kind. Luigi Torchi invented the first direct multiplication machine in 1834: this was also the second key-driven mac... |
2,253 | It wasn't until 1902 that the familiar push-button user interface was developed, with the introduction of the Dalton Adding Machine, developed by James L. Dalton in the United States. |
2,254 | In 1921, Edith Clarke invented the "Clarke calculator", a simple graph-based calculator for solving line equations involving hyperbolic functions. This allowed electrical engineers to simplify calculations for inductance and capacitance in power transmission lines. |
2,255 | The Curta calculator was developed in 1948 and, although costly, became popular for its portability. This purely mechanical hand-held device could do addition, subtraction, multiplication and division. By the early 1970s electronic pocket calculators ended manufacture of mechanical calculators, although the Curta remai... |
2,256 | The first mainframe computers, initially using vacuum tubes and later transistors in the logic circuits, appeared in the 1940s and 1950s. Electronic circuits developed for computers also had application to electronic calculators. |
2,257 | The Casio Computer Company, in Japan, released the Model 14-A calculator in 1957, which was the world's first all-electric compact calculator. It did not use electronic logic but was based on relay technology, and was built into a desk. The IBM 608 plugboard programmable calculator was IBM's first all-transistor produ... |
2,258 | In October 1961, the world's first all-electronic desktop calculator, the British Bell Punch/Sumlock Comptometer ANITA was announced. This machine used vacuum tubes, cold-cathode tubes and Dekatrons in its circuits, with 12 cold-cathode "Nixie" tubes for its display. Two models were displayed, the Mk VII for continent... |
2,259 | The tube technology of the ANITA was superseded in June 1963 by the U.S. manufactured Friden EC-130, which had an all-transistor design, a stack of four 13-digit numbers displayed on a 5-inch cathode ray tube , and introduced Reverse Polish Notation to the calculator market for a price of $2200, which was about three... |
2,260 | There followed a series of electronic calculator models from these and other manufacturers, including Canon, Mathatronics, Olivetti, SCM , Sony, Toshiba, and Wang. The early calculators used hundreds of germanium transistors, which were cheaper than silicon transistors, on multiple circuit boards. Display types used we... |
2,261 | Bulgaria's ELKA 6521, introduced in 1965, was developed by the Central Institute for Calculation Technologies and built at the Elektronika factory in Sofia. The name derives from ELektronen KAlkulator, and it weighed around 8 kg . It is the first calculator in the world which includes the square root function. Later th... |
2,262 | The first desktop programmable calculators were produced in the mid-1960s. They included the Mathatronics Mathatron and the Olivetti Programma 101 which were solid-state, desktop, printing, floating point, algebraic entry, programmable, stored-program electronic calculators. Both could be programmed by the end user a... |
2,263 | Another early programmable desktop calculator was the Casio produced in 1967. It featured a nixie tubes display and had transistor electronics and ferrite core memory. |
2,264 | The Monroe Epic programmable calculator came on the market in 1967. A large, printing, desk-top unit, with an attached floor-standing logic tower, it could be programmed to perform many computer-like functions. However, the only branch instruction was an implied unconditional branch at the end of the operation stack, ... |
2,265 | The first Soviet programmable desktop calculator ISKRA 123, powered by the power grid, was released at the start of the 1970s. |
2,266 | The electronic calculators of the mid-1960s were large and heavy desktop machines due to their use of hundreds of transistors on several circuit boards with a large power consumption that required an AC power supply. There were great efforts to put the logic required for a calculator into fewer and fewer integrated cir... |
2,267 | By 1970, a calculator could be made using just a few chips of low power consumption, allowing portable models powered from rechargeable batteries. The first handheld calculator was a 1967 prototype called Cal Tech, whose development was led by Jack Kilby at Texas Instruments in a research project to produce a portable ... |
2,268 | The first commercially produced portable calculators appeared in Japan in 1970, and were soon marketed around the world. These included the Sanyo ICC-0081 "Mini Calculator", the Canon Pocketronic, and the Sharp QT-8B "micro Compet". The Canon Pocketronic was a development from the "Cal-Tech" project. It had no traditio... |
2,269 | Sharp put in great efforts in size and power reduction and introduced in January 1971 the Sharp EL-8, also marketed as the Facit 1111, which was close to being a pocket calculator. It weighed 1.59 pounds , had a vacuum fluorescent display, rechargeable NiCad batteries, and initially sold for US$395. |
2,270 | However, integrated circuit development efforts culminated in early 1971 with the introduction of the first "calculator on a chip", the MK6010 by Mostek, followed by Texas Instruments later in the year. Although these early hand-held calculators were very costly, these advances in electronics, together with development... |
2,271 | In 1971, Pico Electronics and General Instrument also introduced their first collaboration in ICs, a full single chip calculator IC for the Monroe Royal Digital III calculator. Pico was a spinout by five GI design engineers whose vision was to create single chip calculator ICs. Pico and GI went on to have significant s... |
2,272 | The first truly pocket-sized electronic calculator was the Busicom LE-120A "HANDY", which was marketed early in 1971. Made in Japan, this was also the first calculator to use an LED display, the first hand-held calculator to use a single integrated circuit , the Mostek MK6010, and the first electronic calculator to run... |
2,273 | The first European-made pocket-sized calculator, DB 800 was made in May 1971 by Digitron in Buje, Croatia with four functions and an eight-digit display and special characters for a negative number and a warning that the calculation has too many digits to display. |
2,274 | The first American-made pocket-sized calculator, the Bowmar 901B , measuring 5.2 by 3.0 by 1.5 inches , came out in the Autumn of 1971, with four functions and an eight-digit red LED display, for US$240, while in August 1972 the four-function Sinclair Executive became the first slimline pocket calculator measuring 5.4 ... |
2,275 | The first Soviet Union made pocket-sized calculator, the Elektronika B3-04 was developed by the end of 1973 and sold at the start of 1974. |
2,276 | One of the first low-cost calculators was the Sinclair Cambridge, launched in August 1973. It retailed for £29.95 , or £5 less in kit form, and later models included some scientific functions. The Sinclair calculators were successful because they were far cheaper than the competition; however, their design led to slow... |
2,277 | Meanwhile, Hewlett-Packard had been developing a pocket calculator. Launched in early 1972, it was unlike the other basic four-function pocket calculators then available in that it was the first pocket calculator with scientific functions that could replace a slide rule. The $395 HP-35, along with nearly all later HP ... |
2,278 | The first Soviet scientific pocket-sized calculator the "B3-18" was completed by the end of 1975. |
2,279 | In 1973, Texas Instruments introduced the SR-10, an algebraic entry pocket calculator using scientific notation for $150. Shortly after the SR-11 featured an added key for entering pi . It was followed the next year by the SR-50 which added log and trig functions to compete with the HP-35, and in 1977 the mass-market... |
2,280 | In 1978, a new company, Calculated Industries arose which focused on specialized markets. Their first calculator, the Loan Arranger was a pocket calculator marketed to the Real Estate industry with preprogrammed functions to simplify the process of calculating payments and future values. In 1985, CI launched a calcula... |
2,281 | The first programmable pocket calculator was the HP-65, in 1974; it had a capacity of 100 instructions, and could store and retrieve programs with a built-in magnetic card reader. Two years later the HP-25C introduced continuous memory, i.e., programs and data were retained in CMOS memory during power-off. In 1979, HP ... |
2,282 | The first Soviet pocket battery-powered programmable calculator, Elektronika B3-21, was developed by the end of 1976 and released at the start of 1977. The successor of B3-21, the Elektronika B3-34 wasn't backward compatible with B3-21, even if it kept the reverse Polish notation . Thus B3-34 defined a new command set,... |
2,283 | This series of calculators was also noted for a large number of highly counter-intuitive mysterious undocumented features, somewhat similar to "synthetic programming" of the American HP-41, which were exploited by applying normal arithmetic operations to error messages, jumping to nonexistent addresses and other method... |
2,284 | A similar hacker culture in the US revolved around the HP-41, which was also noted for a large number of undocumented features and was much more powerful than B3-34. |
2,285 | Through the 1970s the hand-held electronic calculator underwent rapid development. The red LED and blue/green vacuum fluorescent displays consumed a lot of power and the calculators either had a short battery life or were large so that they could take larger, higher capacity batteries. In the early 1970s liquid-crysta... |
2,286 | A more successful series of calculators using a reflective DSM-LCD was launched in 1972 by Sharp Inc with the Sharp EL-805, which was a slim pocket calculator. This, and another few similar models, used Sharp's Calculator On Substrate technology. An extension of one glass plate needed for the liquid crystal display wa... |
2,287 | In the mid-1970s the first calculators appeared with field-effect, twisted nematic LCDs with dark numerals against a grey background, though the early ones often had a yellow filter over them to cut out damaging ultraviolet rays. The advantage of LCDs is that they are passive light modulators reflecting light, which r... |
2,288 | There were also improvements to the electronics inside the calculators. All of the logic functions of a calculator had been squeezed into the first "calculator on a chip" integrated circuits in 1971, but this was leading edge technology of the time and yields were low and costs were high. Many calculators continued to... |
2,289 | The power consumption of the integrated circuits was also reduced, especially with the introduction of CMOS technology. Appearing in the Sharp "EL-801" in 1972, the transistors in the logic cells of CMOS ICs only used any appreciable power when they changed state. The LED and VFD displays often required added driver tr... |
2,290 | With this low power consumption came the possibility of using solar cells as the power source, realised around 1978 by calculators such as the Royal Solar 1, Sharp EL-8026, and Teal Photon. |
2,291 | At the start of the 1970s, hand-held electronic calculators were very costly, at two or three weeks' wages, and so were a luxury item. The high price was due to their construction requiring many mechanical and electronic components which were costly to produce, and production runs that were too small to exploit economi... |
2,292 | By 1976, the cost of the cheapest four-function pocket calculator had dropped to a few dollars, about 1/20 of the cost five years before. The results of this were that the pocket calculator was affordable, and that it was now difficult for the manufacturers to make a profit from calculators, leading to many firms dropp... |
2,293 | The first calculator capable of symbolic computing was the HP-28C, released in 1987. It could, for example, solve quadratic equations symbolically. The first graphing calculator was the Casio fx-7000G released in 1985. |
2,294 | The two leading manufacturers, HP and TI, released increasingly feature-laden calculators during the 1980s and 1990s. At the turn of the millennium, the line between a graphing calculator and a handheld computer was not always clear, as some very advanced calculators such as the TI-89, the Voyage 200 and HP-49G could d... |
2,295 | The HP 12c financial calculator is still produced. It was introduced in 1981 and is still being made with few changes. The HP 12c featured the reverse Polish notation mode of data entry. In 2003 several new models were released, including an improved version of the HP 12c, the "HP 12c platinum edition" which added more... |
2,296 | Calculated Industries competed with the HP 12c in the mortgage and real estate markets by differentiating the key labeling; changing the "I", "PV", "FV" to easier labeling terms such as "Int", "Term", "Pmt", and not using the reverse Polish notation. However, CI's more successful calculators involved a line of construc... |
2,297 | In most countries, students use calculators for schoolwork. There was some initial resistance to the idea out of fear that basic or elementary arithmetic skills would suffer. There remains disagreement about the importance of the ability to perform calculations in the head, with some curricula restricting calculator us... |
2,298 | Personal computers often come with a calculator utility program that emulates the appearance and functions of a calculator, using the graphical user interface to portray a calculator. Examples include the Windows Calculator, Apple's Calculator, and KDE's KCalc. Most personal data assistants and smartphones also have s... |
2,299 | The fundamental difference between a calculator and computer is that a computer can be programmed in a way that allows the program to take different branches according to intermediate results, while calculators are pre-designed with specific functions built in. The distinction is not clear-cut: some devices classed as... |
2,300 | For instance, instead of a hardware multiplier, a calculator might implement floating point mathematics with code in read-only memory , and compute trigonometric functions with the CORDIC algorithm because CORDIC does not require much multiplication. Bit serial logic designs are more common in calculators whereas bit p... |
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