Microcode - Knowledge

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difference is that in a custom logic design, changes to the individual steps require the hardware to be redesigned. Using microcode, all that changes is the code stored in the memory containing the microcode. This makes it much easier to fix problems in a microcode system. It also means that there is no effective limit to the complexity of the instructions, it is only limited by the amount of memory one is willing to use.

1679:"Horizontal microcode has several discrete micro-operations that are combined in a single microinstruction for simultaneous operation." Horizontal microcode is typically contained in a fairly wide control store; it is not uncommon for each word to be 108 bits or more. On each tick of a sequencer clock a microcode word is read, decoded, and used to control the functional elements that make up the CPU. 541:

various control lines, the microcode engine is connected to these lines instead, and these are turned on and off as the engine reads the microcode instructions in sequence. The microcode instructions are often bit encoded to those lines, for instance, if bit 8 is true, that might mean that the ALU should be paused awaiting data. In this respect microcode is somewhat similar to the paper rolls in a

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a full 32-bit ALU that performs the same addition in a single cycle. These differences could be implemented in control logic, but the cost of implementing a completely different decoder for each machine would be prohibitive. Using microcode meant all that changed was the code in the ROM. For instance, one machine might include a

743:; higher-level instructions mean greater programmer productivity, so an important advantage of microcode was the relative ease by which powerful machine instructions can be defined. The ultimate extension of this are "Directly Executable High Level Language" designs, in which each statement of a high-level language such as 1647:

program is intended to execute the bits in the same way as the electronics, and allows much more freedom to debug the microprogram. After the microprogram is finalized, and extensively tested, it is sometimes used as the input to a computer program that constructs logic to produce the same data. This

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have several execution units. Even simple computers usually have one unit to read and write memory, and another to execute user code. These elements could often be brought together as a single chip. This chip comes in a fixed width that would form a "slice" through the execution unit. These are known

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The B700 "microprocessor" execute application-level opcodes using sequences of 16-bit microinstructions stored in main memory; each of these is either a register-load operation or mapped to a single 56-bit "nanocode" instruction stored in read-only memory. This allows comparatively simple hardware to

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The industry responded to the concept of RISC with both confusion and hostility, including a famous dismissive article by the VAX team at Digital. A major point of contention was that implementing the instructions outside of the processor meant it would spend much more time reading those instructions

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to the compiler, which is the entire purpose of using a compiler in the first place. The basic concept was soon picked up by university researchers in California, where simulations suggested such designs would trivially outperform even the fastest conventional designs. It was one such project, at the

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The outcome of this design was that customers could use a low-end model of the family to develop their software, knowing that if more performance was ever needed, they could move to a faster version and nothing else would change. This lowered the barrier to entry and the 360 was a runaway success. By

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But the real value in the 360 line was that one could build a series of machines that were completely different internally, yet run the same ISA. For a low-end machine, one might use an 8-bit ALU that requires multiple cycles to complete a single 32-bit addition, while a higher end machine might have

2249:) are frequently used by modern compilers. Even immediate to stack (i.e., memory result) arithmetic operations are commonly employed. Although such memory operations, often with varying length encodings, are more difficult to pipeline, it is still fully feasible to do so - clearly exemplified by the 1070:

concept. The complex microcode engine and its associated ROM is reduced or eliminated completely, and those circuits instead dedicated to things like additional registers or a wider ALU, which increases the performance of every program. When complex sequences of instructions are needed, this is left

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almost always used the simplest one, instead of the one most directly representing the code. They learned that this was because those instructions were always implemented in hardware, and thus run the fastest. Using the other instruction might offer higher performance on some machines, but there was

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The basic idea behind microcode is to replace the custom hardware logic implementing the instruction sequencing with a series of simple instructions run in a "microcode engine" in the processor. Whereas a custom logic system might have a series of diodes and gates that output a series of voltages on

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had instruction sets that were simple enough to be implemented in dedicated logic. By this time, the control logic could be patterned into the same die as the CPU, making the difference in cost between ROM and logic less of an issue. However, it was not long before these companies were also facing

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controls that part of the CPU. With this type of microcode, a designer explicitly chooses to make a slower CPU to save money by reducing the unused bits in the control store; however, the reduced complexity may increase the CPU's clock frequency, which lessens the effect of an increased number of

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is unique among System/360 models in using the top 16 K bytes of core storage to hold the control storage for the microprogram. The 2025 uses a 16-bit microarchitecture with seven control words (or microinstructions). After system maintenance or when changing operating mode, the microcode is

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For each tick it is common to find that only some portions of the CPU are used, with the remaining groups of bits in the microinstruction being no-ops. With careful design of hardware and microcode, this property can be exploited to parallelise operations that use different areas of the CPU; for

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Meta 4 Series 16 computer system was a user-microprogammable system first available in 1970. The microcode had a primarily vertical style with 32-bit microinstructions. The instructions were stored on replaceable program boards with a grid of bit positions. One (1) bits were represented by small

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has full 32-bit data paths and implements the general-purpose registers in a special unit of higher-speed core memory. The Model 65 through the Model 195 have larger data paths and implement the general-purpose registers in faster transistor circuits. In this way, microprogramming enabled IBM to

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processors are designed to execute every instruction (as long as it is in the cache) in a single cycle. This is very similar to the way CPUs with microcode execute one microinstruction per cycle. VLIW processors have instructions that behave similarly to very wide horizontal microcode, although

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were used to alleviate this. High-level machine instructions, made possible by microcode, helped further, as fewer more complex machine instructions require less memory bandwidth. For example, an operation on a character string can be done as a single machine instruction, thus avoiding multiple

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Microcode simplified the job by allowing much of the processor's behaviour and programming model to be defined via microprogram routines rather than by dedicated circuitry. Even late in the design process, microcode could easily be changed, whereas hard-wired CPU designs were very cumbersome to

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In vertical microcode, each microinstruction is significantly encoded, that is, the bit fields generally pass through intermediate combinatory logic that, in turn, generates the control and sequencing signals for internal CPU elements (ALU, registers, etc.). This is in contrast with horizontal

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Each microinstruction in a microprogram provides the bits that control the functional elements that internally compose a CPU. The advantage over a hard-wired CPU is that internal CPU control becomes a specialized form of a computer program. Microcode thus transforms a complex electronic design

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While companies continued to compete on the complexity of their instruction sets, and the use of microcode to implement these was unquestioned, in the mid-1970s an internal project in IBM was raising serious questions about the entire concept. As part of a project to develop a high-performance

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A processor's microprograms operate on a more primitive, totally different, and much more hardware-oriented architecture than the assembly instructions visible to normal programmers. In coordination with the hardware, the microcode implements the programmer-visible architecture. The underlying

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The distinction between custom logic and microcode may seem small, one uses a pattern of diodes and gates to decode the instruction and produce a sequence of signals, whereas the other encodes the signals as microinstructions that are read in sequence to produce the same results. The critical

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uses an 8-bit microarchitecture with only a few hardware registers; everything that the programmer saw is emulated by the microprogram. The microcode for this model is also held on special punched cards, which are stored inside the machine in a dedicated reader per card, called "CROS" units

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in computer software. His initial implementation consisted of a pair of matrices: the first one generated signals in the manner of the Whirlwind control store, while the second matrix selected which row of signals (the microprogram instruction word, so to speak) to invoke on the next cycle.

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with an instruction encoding similar to RISC or traditional microcode. A hardwired instruction decode unit directly emits microoperations for common x86 instructions, but falls back to a more traditional microcode ROM containing microoperations for more complex or rarely used instructions.

1850:, use machine code, running in a special mode that gives it access to special instructions, special registers, and other hardware resources unavailable to regular machine code, to implement some instructions and other functions, such as page table walks on Alpha processors. This is called 2033:

microcodes to be fixed by patching their microprograms, rather than requiring the entire chips to be replaced. A second prominent example is the set of microcode patches that Intel offered for some of their processor architectures of up to 10 years in age, in a bid to counter the security

1034:, all implemented in microcode. This did not come without cost, according to early articles, about 20% of the chip's surface area (and thus cost) is the microcode system. and later estimates suggest approximately 23,000 of the systems 68,000 gates were part of the microcode system. 1835:

microcode, in which the bit fields either directly produce the control and sequencing signals or are only minimally encoded. Consequently, vertical microcode requires smaller instruction lengths and less storage, but requires more time to decode, resulting in a slower CPU clock.

480:(ALU) which performs instructions such as addition or comparing two numbers, circuits for reading and writing data to external memory, and small areas of onboard memory to store these values while they are being processed. In most designs, additional high-performance memory, the 843:

design many System/360 models with substantially different hardware and spanning a wide range of cost and performance, while making them all architecturally compatible. This dramatically reduces the number of unique system software programs that must be written for each model.

411:, thereby enabling greater flexibility in designing and altering instructions. Moreover, it facilitates the construction of complex multi-step instructions, while simultaneously reducing the complexity of computer circuits. The act of writing microcode is often referred to as 1103:

Some processor designs use machine code that runs in a special mode, with special instructions, available only in that mode, that have access to processor-dependent hardware, to implement some low-level features of the instruction set. The DEC Alpha, a pure RISC design, used

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and audio processor, utilizes microcode; it is possible to implement new effects or tweak the processor to achieve the desired output. Some notable examples of custom RCP microcode include the high-resolution graphics, particle engines, and unlimited draw distances found in

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series. This allowed the machines to have a very complex instruction set, including operations that matched high-level language constructs like formatting binary values as decimal strings, storing the complex series of instructions needed for this task in low cost memory.

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The complex instructions in heavily microcoded implementations may not take much extra machine resources, except for microcode space. For example, the same ALU is often used to calculate an effective address and to compute the result from the operands, e.g., the original

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is implemented with radically different hardware including bit-addressable main memory but has a similar multi-layer organisation. The operating system preloads the interpreter for whatever language is required. These interpreters present different virtual machines for

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with an emulator feature. Microprograms are carefully designed and optimized for the fastest possible execution, as a slow microprogram would result in a slow machine instruction and degraded performance for related application programs that use such instructions.

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Microprogramming is still used in modern CPU designs. In some cases, after the microcode is debugged in simulation, logic functions are substituted for the control store. Logic functions are often faster and less expensive than the equivalent microprogram memory.

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open for other operations. Internally, however, these instructions are not separate operations, but sequences of the operations the units actually perform. Converting a single instruction read from memory into the sequence of internal actions is the duty of the

626:. In the latter case, the CPU initialization process loads microcode into the control store from another storage medium, with the possibility of altering the microcode to correct bugs in the instruction set, or to implement new machine instructions. 1212:

has separate instruction fetch (I-unit) and execution (E-unit) to provide high performance. The I-unit is hardware controlled. The E-unit is microprogrammed; the control words are 108 bits wide on a basic 360/85 and wider if an emulator feature is

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uses hardwired circuitry to fetch and decode instructions, using microcode only to execute instructions; register-register move and arithmetic instructions required only one microinstruction, allowing them to be completed in one clock cycle. The

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The debate raged until the first commercial RISC designs emerged in the second half of the 1980s, which easily outperformed the most complex designs from other companies. By the late 1980s it was over; even DEC was abandoning microcode for their

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Microcode remained relatively rare in computer design as the cost of the ROM needed to store the code was not significantly different than using a custom control store. This changed through the early 1960s with the introduction of mass-produced

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they are using. So to add two numbers, for instance, the compiler may output instructions to load one of the values into one register, the second into another, call the addition function in the ALU, and then write the result back out to memory.

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For this type of micromachine to implement a JUMP instruction with the address following the opcode, the microcode might require two clock ticks. The engineer designing it would write microassembler source code looking something like this:

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Conditionals were implemented by providing a way that a single line in the control store could choose from alternatives in the second matrix. This made the control signals conditional on the detected internal signal. Wilkes coined the term

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WCS offers several advantages including the ease of patching the microprogram and, for certain hardware generations, faster access than ROMs can provide. User-programmable WCS allows the user to optimize the machine for specific purposes.

885:: a two-dimensional lattice, where one dimension accepts "control time pulses" from the CPU's internal clock, and the other connects to control signals on gates and other circuits. A "pulse distributor" takes the pulses generated by the 1079:

from memory, thereby slowing overall performance no matter how fast the CPU itself ran. Proponents pointed out that simulations clearly showed the number of instructions was not much greater, especially when considering compiled code.

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A similar approach was used by Digital Equipment Corporation (DEC) in their VAX family of computers. As a result, different VAX processors use different microarchitectures, yet the programmer-visible architecture does not change.

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and thus its microcode for multiplying two numbers might be only a few lines line, whereas on the same machine without the FPU this would be a program that did the same using multiple additions, and all that changed was the ROM.

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As the sequence of instructions needed to complete this higher-level concept, "add these two numbers in memory", may require multiple instructions, this can represent a performance bottleneck if those instructions are stored in

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metal squares that were sensed by amplifiers, zero (0) bits by the absence of the squares. The system could be configured with up to 4K 16-bit words of microstore. One of Digital Scientific's products was an emulator for the

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instructions for the processor. In microcoded processors, fetching and decoding those instructions, and executing them, may be done by microcode. To avoid confusion, each microprogram-related element is differentiated by the

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were far too simple to require microcode, and were more similar to earlier mainframes in terms of their instruction sets and the way they were decoded. But it was not long before their designers began using more powerful

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allows a programmer to define the table of bits symbolically. Because of its close relationship to the underlying architecture, "microcode has several properties that make it difficult to generate using a compiler." A

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The IBM System/360 has a 32-bit architecture with 16 general-purpose registers, but most of the System/360 implementations use hardware that implements a much simpler underlying microarchitecture; for example, the

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Non-RISC instructions inherently perform more work per instruction (on average), and are also normally highly encoded, so they enable smaller overall size of the same program, and thus better use of limited cache

1096:'s fetch and decode hardware fetches instructions and decodes them into series of micro-operations that are passed on to the execution unit, which schedules and executes the micro-operations, possibly doing so 1205:

has two internal datapaths which operated in parallel: a 32-bit datapath used for arithmetic operations, and an 8-bit data path used in some logical operations. The control store uses 90-bit microinstructions.

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hardware need not have a fixed relationship to the visible architecture. This makes it easier to implement a given instruction set architecture on a wide variety of underlying hardware micro-architectures.

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workstation used a microcoded design but, unlike many computers, the microcode engine is not hidden from the programmer in a layered design. Applications take advantage of this to accelerate performance.

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picks the next word of the control store. A sequencer is mostly a counter, but usually also has some way to jump to a different part of the control store depending on some data, usually data from the

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To properly perform an instruction, the various circuits have to be activated in order. For instance, it is not possible to add two numbers if they have not yet been loaded from memory. In

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and breaks them up into eight separate time pulses, each of which activates a different row of the lattice. When the row is activated, it activates the control signals connected to it.

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before doing so (vertical microcode). Consequently, each horizontal microinstruction is wider (contains more bits) and occupies more storage space than a vertical microinstruction.

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The team came to a radical conclusion: "Imposing microcode between a computer and its users imposes an expensive overhead in performing the most frequently executed instructions."

523:", that most closely matches the ultimate operation can reduce the number of instructions to one, saving memory used by the program code and improving performance by leaving the 1631:

family is one of the best known examples of bit slice elements. The parts of the execution units and the whole execution units are interconnected by a bundle of wires called a

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is an example of a microprocessor using a PLA for instruction decode and sequencing. The PLA is visible in photomicrographs of the chip, and its operation can be seen in the

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A CPU that uses microcode generally takes several clock cycles to execute a single instruction, one clock cycle for each step in the microprogram for that instruction. Some

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has 8-bit data paths to the ALU and 16-bit data paths to main memory and also implemented the general-purpose registers in a special unit of higher-speed core memory. The

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state machine circuitry. While such hard-wired processors were very efficient, the need for powerful instruction sets with multi-step addressing and complex operations (

801:(ROM) (instead of combinational logic) mainly for instruction decoding, and let a simple state machine (without much, or any, microcode) do most of the sequencing. The 4437: 974:

is stored in the two large square blocks in the upper right and controlled by circuitry to the right of it. It takes up a significant amount of the total chip surface.

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The design trend toward heavily microcoded processors with complex instructions began in the early 1960s and continued until roughly the mid-1980s. At that point the

720:. Each step needed to fetch, decode, and execute the machine instructions (including any operand address calculations, reads, and writes) was controlled directly by 438:, and so forth. This approach provides a relatively straightforward method of ensuring software compatibility between different products within a processor family. 3251: 2278:

typically without such fine-grained control over the hardware as provided by microcode. RISC instructions are sometimes similar to the narrow vertical microcode.

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At the hardware level, processors contain a number of separate areas of circuitry, or "units", that perform different tasks. Commonly found units include the

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Microprograms consist of series of microinstructions, which control the CPU at a very fundamental level of hardware circuitry. For example, a single typical

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Some vertical microcode is just the assembly language of a simple conventional computer that is emulating a more complex computer. Some processors, such as

4227:(15 August 1979 ed.). Texas Instruments Archives, RG-20 accession 94-08, Box 10, 45C. DeGolyer Library, Southern Methodist University, Dallas, TX USA. 3502: 2554: 1826:

example, in the case above, the ALU is not required during the first tick, so it could potentially be used to complete an earlier arithmetic instruction.

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In a typical implementation a horizontal microprogram word comprises fairly tightly defined groups of bits. For example, one simple arrangement might be:

1183:(Capacitor Read-Only Storage). Another CROS unit is added for machines ordered with 1401/1440/1460 emulation and for machines ordered with 1620 emulation. 1060:

no way to know what machine they were running on. This defeated the purpose of using microcode in the first place, which was to hide these distinctions.

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has 8-bit data paths to the arithmetic logic unit (ALU) and main memory and implemented the general-purpose registers in a special unit of higher-speed

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As transistors grew cheaper, horizontal microcode came to dominate the design of CPUs using microcode, with vertical microcode being used less often.

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uses 56-bit control words. The 2040 box implements both the System/360 main processor and the multiplex channel (the I/O processor). This model uses

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The machine resources devoted to rarely used complex instructions are better used for expediting performance of simpler, commonly used instructions.

1226:) pulsed by a sequencer with conditional execution. Wires routed through the cores are enabled for various data and logic elements in the processor. 4623: 3535: 1299:

produced computers in which the microcode is accessible to the user; this allows the creation of custom assembler level instructions. Microdata's

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Fountainhead Processor are examples of this. During the 1970s, CPU speeds grew more quickly than memory speeds and numerous techniques such as

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Programming has largely moved away from assembly level, so it's no longer worthwhile to provide complex instructions for productivity reasons.

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For example, an x86 might look up microoperations from microcode to handle complex multistep operations such as loop or string instructions,

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challenge (the control of a CPU) into a less complex programming challenge. To take advantage of this, a CPU is divided into several parts:

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set is a fast memory containing the data of the central processing unit. It may include registers visible to application programs, such as

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designs, and CISC processors switched to using hardwired circuitry, rather than microcode, to perform many functions. For example, the

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To simultaneously control all processor's features in one cycle, the microinstruction is often wider than 50 bits; e.g., 128 bits on a

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performs calculations, usually addition, logical negation, a right shift, and logical AND. It often performs other functions, as well.

4967: 459:. In this context, all code within a device is termed microcode, whether it is microcode or machine code. For instance, updates to a 3850: 407:

data, or other input into sequences of detailed circuit-level operations. It separates the machine instructions from the underlying

380:. It consists of a set of hardware-level instructions that implement the higher-level machine code instructions or control internal 5616: 1325:(IMPI) using a horizontal microcode format. The so-called vertical microcode layer implements the System/38's hardware-independent 3934: 2804: 5688: 1572:

and always some part of the control store. The simplest sequencer is just a register loaded from a few bits of the control store.

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WepSIM: An Online Interactive Educational Simulator Integrating Microdesign, Microprogramming, and Assembly Language Programming

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general-purpose CPUs in contemporary desktops and laptops, it functions only as a fallback path for scenarios that the faster

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has a hardwired IBox unit to fetch and decode instructions, which it hands to a microcoded EBox unit to be executed, and the

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Some commercial machines, for example IBM 360/85, have both a read-only storage and a writable control store for microcode.

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may decode instructions in hardware and determine the microcode address for processing the instruction in parallel with the

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Digital Scientific Meta 4 Computer System Typical ROM Pattern Listing and Program To Simulate The IBM 1130 Instruction Set

1917:. In this design, rather than storing the microcode in ROM or hard-wired logic, the microcode is stored in a RAM called a 6395: 5536: 3068:

Digest of Papers Compcon Spring '90. Thirty-Fifth IEEE Computer Society International Conference on Intellectual Leverage

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Simpler instruction sets allow direct execution by hardware, avoiding the performance penalty of microcoded execution.

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Microcode was originally developed as a simpler method of developing the control logic for a computer. Initially, CPU

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from 1975 through the early 1980s. It was used to implement three different computer architectures in microcode: the

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Analysis shows complex instructions are rarely used, hence the machine resources devoted to them are largely wasted.

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are examples of highly encoded "vertical" microsequencer implementations of the Intel 8086/8088, 8051, and MOS 6502.

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IBM horizontally microcoded processors had multiple micro-orders and register select fields that required decoding.

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reputedly uses a hard-wired control store consisting of wires threaded through ferrite cores, known as "the laces".

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are microprogrammable; in fact, VU1 is only accessible via microcode for the first several generations of the SDK.

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as well. Early designs were extremely simple, and even the more powerful 8-bit designs of the mid-1970s like the

340: 4149:"A microcode reliability update is available that improves the reliability of systems that use Intel processors" 3559: 3493: 2562: 1988: 1100:. Complex instructions are implemented by microcode that consists of predefined sequences of micro-operations. 568:

in order to delegate sub-tasks that must be performed essentially asynchronously in parallel. For example, the

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processors include instructions that can take a very long time to execute. Such variations interfere with both

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IBM System/360 Special Feature Description 709/7090/7094 Compatibility Feature for IBM System/360 Model 85

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Intel 64 and IA-32 Architectures Software Developer's Manual, Volume 3A: System Programming Guide, Part 1

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for which it is designed, as it constitutes an inherent part of the particular processor design itself.

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designs, the proper ordering of these instructions is largely up to the programmer, or at least to the

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When both vertical and horizontal microcode are used, the horizontal microcode may be referred to as

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programmer, does not normally see or change microcode. Unlike machine code, which often retains some

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implement patchable microcode (patch by operating system). Such microcode is patched to device's

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4096 x 75-bit SRAM writable control store: 74-bit microinstruction with 1 parity bit (18 fields)

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introduced the concept of a control store as a way to simplify computer design and move beyond

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Engineers normally write the microcode during the design phase of a processor, storing it in a

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High Availability and Scalability of Mainframe Environments using System z and z/OS as example

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Complex microcoded instructions may require many clock cycles that vary, and are difficult to

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Texas Instruments Model 990 Computer MDS-990 Microcode Development System Programmer's Guide

3911: 6476: 6412: 5998: 5720: 5610: 5557: 5089: 4802: 4658: 4640: 4378: 4365:"Microprogramming and the Design of the Control Circuits in an Electronic Digital Computer" 4174:"Server Products - BIOS Update required when Missing Microcode message is seen during POST" 4123: 2415: 2393: 2222: 2062: 1656:(ROM) control store. This reduces the cost to produce, and the electricity used by, a CPU. 1607: 1569: 1398: 1273:

act either as a mainframe peripheral controller or to be packaged as a standalone computer.

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Some machines offer user-programmable writable control stores as an option, including the

1749:# The sequencer instruction "next" means just add 1 to the control word address. 8: 6523: 6508: 6328: 6179: 6161: 6125: 6113: 5767: 5714: 5491: 5407: 5289: 5144: 5039: 4898: 4442: 3880: 3839: 2404: 2342: 1668: 1497: 1345: 946: 802: 721: 660: 75: 4545: 4382: 4298: 2162:

Please help update this article to reflect recent events or newly available information.

2042:– which went public at the start of 2018. A microcode update can be installed by Linux, 1880:

selects which part of the CPU will be controlled by this word of the control store. The

6380: 6372: 6224: 6199: 6003: 5878: 5402: 5343: 5223: 4955: 4683: 4394: 4337: 4278: 4232: 3355: 3045: 2523: 2373: 1740:# jump opcode, by copying from the memory data register to the memory address register. 1576: 1475: 1380: 1318: 984: 725: 588: 484:, is used to store temporary values, not just those needed by the current instruction. 385: 771:

Architectures with instruction sets implemented by complex microprograms included the

6559: 6333: 6300: 6216: 6148: 6049: 6039: 6029: 5960: 5955: 5950: 5873: 5802: 5708: 5668: 5301: 5251: 5201: 5177: 5059: 4999: 4994: 4876: 4792: 4422: 4415: 3806: 3763: 3713: 3656: 3380: 3312: 3141: 3083: 2898: 2487: 2282: 2202: 2191: 1376: 1142: 988: 764: 740: 580: 423: 4398: 4282: 4045: 3876: 3049: 2925: 1808:# The instruction decode is not shown, because it is usually a mess, very particular 1734:# moved the program counter to the memory address register. This instruction fetches 1307: 564:

Complex digital processors may also employ more than one (possibly microcode-based)

6503: 6436: 6422: 6277: 6184: 6138: 5945: 5940: 5935: 5930: 5925: 5915: 5785: 5752: 5663: 5658: 5567: 5419: 5414: 5397: 5385: 5324: 4888: 4866: 4752: 4730: 4648: 4501: 4451: 4386: 4341: 4329: 4270: 3872: 3347: 3280: 3075: 3037: 3025: 3003: 2944: 2410: 1731:# To prepare for the next instruction, the instruction-decode microcode has already 1653: 1611: 1505: 1223: 1150: 1044: 798: 600: 361: 53: 3400: 3359: 2964: 1451: 1321:. In practice, the processor implements an instruction set architecture named the 6417: 6402: 6350: 6254: 6229: 6066: 6059: 5910: 5905: 5900: 5839: 5747: 5737: 5459: 5294: 5246: 5009: 4893: 4861: 4762: 4757: 4678: 4068:

Intel Patches All Recent CPUs, Promises Hardware Fixes For Upcoming 8th Gen Chips

3800: 3561:

The Digital Scientific Meta 4 Series 16 Computer System Preliminary System Manual

3528:

Digital Scientific Meta 4 Computer System Read-Only Memory (ROM) Reference Manual

3374: 2607: 2481: 2349: 2334: 2294: 2022: 1814:# Many CPUs have several ways to calculate the address, rather than just fetching 1584: 1471: 1444: 1433: 1422: 1385: 1146: 1031: 1011:

the problem of introducing higher-performance designs but still wanting to offer

987:

that allowed for more complex ISAs. By the mid-1970s, most new minicomputers and

713: 692: 460: 415:, and the microcode in a specific processor implementation is sometimes termed a 219: 115: 4560: 3244:

Field Engineering Theory of Operation, 2030 Processing Unit, System/360 Model 30

1516:. Such processors implemented microcode ROM and microcode SRAM in their silicon. 1051:

began examining huge volumes of performance data from their customer's 360 (and

403:

Housed in special high-speed memory, microcode translates machine instructions,

6528: 6362: 6345: 6338: 6234: 6091: 5828: 5742: 5673: 5256: 5218: 5167: 5162: 5157: 4871: 4695: 4595: 4356: 4313: 2420: 2262: 2000: 1847: 1737:# the target address of the jump instruction from the memory word following the 1639: 1615: 1565: 1558: 1467: 1125: 1121: 1023: 1003: 971: 893: 855: 790: 435: 193: 93: 4390: 3079: 2753: 1936:; there are also commercial machines that use writable microcode, such as the 1782:# The sequencer instruction is to jump to the start of the instruction decode. 1776:# This gives the memory system a clock tick to finish the fetch started on the 6569: 6548: 6323: 6239: 5279: 5261: 5054: 4747: 3868: 3338: 3137: 3063: 1721:# This is just a label, the ordinary way assemblers symbolically represent a 1588: 1408: 1314: 739:

From the 1940s to the late 1970s, a large portion of programming was done in

618: 481: 404: 5182: 4574:, March 2013, by Ben Hawkes, archived from the original on September 7, 2015 4333: 4274: 3351: 2555:"IBM pSeries Servers - Microcode Update for Ultrastar 73LZX (US73) 18/36 GB" 1746:# instruction to the memory data register for use by the instruction decode. 850:

Microprogramming also reduces the cost of field changes to correct defects (

6533: 6471: 6287: 6264: 6076: 5797: 4735: 4019: 3300: 3288: 2648:"ISO/IEC/IEEE 24765:2017(en) Systems and software engineering — Vocabulary" 2066: 2026: 1632: 1591:; that is, two registers can be read, and a third written at the same time. 999:, which included high-level instruction not unlike those found in the 360. 979: 882: 851: 752: 612: 565: 553: 542: 529: 377: 148: 68: 3629: 3041: 2483:

Encyclopedia of Computer Science and Technology: Volume 28 - Supplement 13

1820:# jump instruction, those CPUs have a family of related jump instructions. 1437: 1426: 1415: 1022:

Among the ultimate implementations of microcode in microprocessors is the

6318: 6282: 5993: 5965: 5823: 5678: 4601: 4148: 3304: 3284: 2844:(Technical report). MIT Servomechanisms Laboratory. R-127. Archived from 2778: 2435: 2326: 2290: 2014: 1817:# it from the word following the op-code. Therefore, rather than just one 1811:# to the exact processor being emulated. Even this example is simplified. 1624: 1341: 1248:

minicomputers are microprogrammed. The task of writing microcode for the

1157: 1093: 1088: 925: 909:

to describe this feature and distinguish it from a simple control store.

760: 747:

is entirely and directly executed by microcode, without compilation. The

587:

among different processors in a family, microcode only runs on the exact

505: 463:'s microcode often encompass updates to both its microcode and firmware. 408: 289: 270: 138: 133: 3678:"CS-323: High Performance Microprocessors – Chapter 1. Microprogramming" 3007: 2750:

Often denoted a ROM/PLA control store in the context of usage in a CPU;

6204: 6194: 6189: 6171: 6071: 6044: 5306: 5139: 5109: 4829: 4586:, 2002, by Alexander Wolfe, archived from the original on March 9, 2003 4455: 3127:"Part I / Common Architecture, Chapter 6 Common PALcode Architecture". 2388: 2258: 1960: 1941: 1843: 1628: 1536: 1520: 1334: 1052: 1016: 937: 918: 806: 775: 105: 3942:. Fourth Edition. IBM. September 1974. pp. 98, 245. GA22-7000-4. 3840:"Writable instruction set, stack oriented computers: The WISC Concept" 3419: 2281:

Microcode has been popular in application-specific processors such as

1486: 6295: 6034: 5104: 5082: 3462: 2589:"The central processing unit (CPU): Its components and functionality" 2430: 1956: 1855: 1839: 1644: 1129: 1084: 1007: 966: 929: 886: 552:

The lowest layer in a computer's software stack is traditionally raw

3495:

Digital Scientific Meta 4 Series 16 Computer System Reference Manual

2082: 1241:

processors with the exception of the PDP-11/20, are microprogrammed.

6310: 5129: 4582: 4568:(fixes the issues when running 32-bit virtual machines in PAE mode) 4512:

external links, and converting useful links where appropriate into

3393: 2425: 2399: 2367: 1463: 1456: 1354: 1330: 1179: 1172: 1056: 573: 569: 524: 509: 492: 455: 427: 143: 63: 4109: 1198:

units, but with an inductive pickup (Transformer Read-only Store).

5119: 5077: 3274: 2246: 2245:

The simpler non-RISC instructions (i.e., involving direct memory

2050: 2043: 1851: 1743:# This gives the memory system two clock ticks to fetch the next 1638:

Programmers develop microprograms, using basic software tools. A

1286: 1219: 1113: 1105: 516:, which differ only in where they look to find the two operands. 284: 240: 3277:"Implementation and Performance Evaluation of the PDP-11 Family" 1842:

processors and the CMOS microprocessors on later IBM mainframes

561:

prefix: microinstruction, microassembler, microprogrammer, etc.

5134: 5099: 5064: 4014: 2330: 2322: 2254: 2058: 2054: 1964: 1554: 1513: 1303:

operating system design makes extensive use of this capability.

1238: 1234: 992: 877: 520: 446: 265: 4196:"Model 990/12 LR Computer Depot Maintenance and Repair Manual" 1773:# This places the address of the next instruction into the PC. 1163:

Most models of the IBM System/360 series are microprogrammed:

622:

in the context of computers, which can be either read-only or

5592: 5124: 5094: 4590:

Opteron Exposed: Reverse Engineering AMD K8 Microcode Updates

4054: 3600:. Digital Scientific Corporation. January 1970. M4/005P-170. 3110: 3026:"Comments on "The Case for the Reduced Instruction Computer"" 2353: 1282: 1277: 1230: 389: 316: 3184: 2717:

Manning, B.M.; Mitby, J.S; Nicholson, J.O. (November 1979).

1496:

processors are fully microcoded. x86 processors implemented

1066:

The result of this discovery was what is today known as the

6456: 5604: 5524: 5114: 3071: 2250: 2239: 2180: 2030: 1532: 1501: 1479: 1405: 1067: 744: 488: 312: 249: 244: 3458:"Postmortem: Angel Studios' Resident Evil 2 (N64 Version)" 3122: 3120: 5044: 5034: 2888:"The Best Way to Design an Automatic Calculating Machine" 2813: 2318: 2235: 2018: 1948: 1493: 1117: 996: 991:

were using microcode as well, such as most models of the

933: 782: 772: 638:

microinstruction might specify the following operations:

545:, where the holes represent which key should be pressed. 442: 393: 3869:"Re: What was the size of Microcode in various machines" 3675: 2926:"Simulating the IBM 360/50 mainframe from its microcode" 2205:

RISC has the following advantages over microcoded CISC:

1171:

loaded from the card reader, tape, or other device. The

3764:"PALcode for Alpha Microprocessors System Design Guide" 3117: 2875:

The Best Way to Design an Automatic Calculating Machine

27:

Layer of hardware-level instructions or data structures

3534:. Digital Scientific Corporation. March 1970. 7024MO. 1252:

is detailed in the Pulitzer Prize-winning book titled

1015:. Among early examples of microcode in micros was the 672:

Update the condition codes from the ALU status flags (

3805:. Springer Science & Business Media. p. 31. 3567:. Digital Scientific Corporation. June 1970. 7006MO. 3104:"Pentium Pro Processor At 150, 166, 180, and 200 MHz" 2716: 368:

serves as an intermediary layer situated between the

3501:. Digital Scientific Corporation. May 1971. 7032MO. 3024:

Clark, Douglas; Strecker, William (September 1980).

2719:"Microprogrammed Processor Having PLA Control Store" 2363: 1222:

is microprogrammed with hand wired ferrite cores (a

3334:"Design of a Small Business Data Processing System" 2194:and, what is far more important in modern systems, 2183:design philosophy started becoming more prominent. 1986:) that can be invoked from the console, as part of 1861:Another form of vertical microcode has two fields: 1718:# Any line starting with a number-sign is a comment 736:change. Thus, this greatly facilitated CPU design. 4414: 4370:Proceedings of the Cambridge Philosophical Society 4124:"[ports] Index of /head/sysutils/cpupdate" 4008:Stiller, Andreas; Paul, Matthias R. (1996-05-12). 3969:IBM System/360 Model 85 Functional Characteristics 3449: 3292: 3212:IBM System/360 Model 25 Functional Characteristics 2806:IBM System/360 Model 50 Functional Characteristics 1959:L- and G-machines, a number of IBM System/360 and 1393:Further information on Nintendo 64 microcode: 576:has both a microcoded IBox and a microcoded EBox. 512:has eight variations of the addition instruction, 4496:may not follow Knowledge's policies or guidelines 4465:"How the 8086 processor's microcode engine works" 2987:Cocke, John; Markstein, Victoria (January 1990). 2630:"How the 8086 processor's microcode engine works" 2480:Kent, Allen; Williams, James G. (April 5, 1993). 6546: 4296: 4257:"A Historical Overview of Computer Architecture" 2524:The microarchitecture of Intel, AMD and VIA CPUs 2333:. decode instructions into dynamically buffered 954:the end of the decade, the use of microcode was 4081:"Download Linux* Processor Microcode Data File" 3372: 2683:. May 1990. pp. 3-5–3-32. EK-KA90S-TD-001. 1648:program is similar to those used to optimize a 4355: 3997:. First Edition. IBM. March 1969. GA27-2733-0. 3250:(First ed.). IBM. June 1967. Y24-3360-1. 3237: 3235: 3233: 3064:"The execution pipeline of the Intel i486 CPU" 2986: 2696:VAX 8800 System Technical Description Volume 2 2072: 2046:, Microsoft Windows, or the motherboard BIOS. 2034:vulnerabilities discovered in their designs – 1974:The IBM System/370 includes a facility called 4617: 3847:The Journal of Forth Application and Research 3023: 2965:"Design Philosophy Behind Motorola's MC68000" 2025:. This, for example, has allowed bugs in the 341: 4001: 3975:. SECOND EDITION. IBM. June 1968. A22-6916-1 3366: 3295:Computer Structures: Principles and Examples 3275:Edward A. Snow; Daniel P. Siewiorek (1982). 2834: 2479: 1175:emulation for this model is loaded this way. 789:(CISC). An alternate approach, used in many 519:Using the variation of the instruction, or " 5622:Computer performance by orders of magnitude 4007: 3735:"The What and Why of zEnterprise Millicode" 3230: 3218:. IBM. January 1968. p. 22. A24-3510-0 3163:"The What and Why of zEnterprise Millicode" 3019: 3017: 2623: 2621: 2529:(Report). Technical University of Denmark. 2352:, and special-purpose instructions such as 2111:. Unsourced material may be challenged and 1933: 388:components. While microcode is utilized in 4631: 4624: 4610: 4106:"Intel Microcode Update Utility for Linux" 2517: 2515: 2475: 2473: 2471: 1932:Many experimental prototype computers use 1124:CPUs, starting with the G4 processor, and 372:(CPU) hardware and the programmer-visible 348: 334: 4566:Intel processor microcode security update 4532:Learn how and when to remove this message 4417:Microprogramming Principles and Practices 3676:Neal Harman; Andy Gimblett (2009-10-12). 2989:"The evolution of RISC technology at IBM" 2317:Modern CISC implementations, such as the 2131:Learn how and when to remove this message 1902: 4578:Hole seen in Intel's bug-busting feature 4462: 3427:"Indiana Jones and the Infernal Machine" 3014: 2618: 1925:. Such a computer is sometimes called a 965: 3912:"CPSC 3300 / The Soul of a New Machine" 3837: 3455: 3437:from the original on September 27, 2013 3407:from the original on September 13, 2007 3130:Alpha AXP Architecture Reference Manual 2996:IBM Journal of Research and Development 2982: 2980: 2978: 2962: 2512: 2468: 1674: 1395:Nintendo 64 programming characteristics 1002:The same basic evolution occurred with 14: 6547: 4435: 4412: 4312: 3936:IBM System/370 Principles of Operation 3909: 3819:from the original on November 20, 2016 3798: 3733:Rogers, Bob (September–October 2012). 3732: 3705: 3653:Computer Architecture and Organization 3331: 3160: 2942: 2919: 2917: 2895:The early British computer conferences 2885: 2872: 2751: 2500:from the original on November 20, 2016 1525:wireless network interface controllers 1360:Indiana Jones and the Infernal Machine 995:and, most notably, most models of the 970:The microcode (and "nanocode") of the 4605: 4438:"Microprogram control for SYSTEM/360" 4299:"A Brief History of Microprogramming" 4254: 4044:"9.11: Microcode update facilities". 3866: 3650: 3474:from the original on October 21, 2012 3401:"Interview: Battling the N64 (Naboo)" 2673:VAX 9000 System Technical Description 2582: 2580: 1829: 1348:(RCP), which serves as the console's 961: 695:address for the next microinstruction 532:, another unit within the processor. 430:more robust architectures with wider 5593:Floating-point operations per second 4476: 3891:from the original on 26 January 2009 3780:from the original on August 15, 2011 2975: 2923: 2627: 2586: 2142: 2109:adding citations to reliable sources 2076: 1614:. Together, these elements form an " 1404:The VU0 and VU1 vector units in the 669:Store the result value in register 8 579:A high-level programmer, or even an 426:of smaller scale and simplicity can 422:Through extensive microprogramming, 4561:A Brief History of Microprogramming 2914: 2838:Whirlwind I Computer Block Diagrams 2835:Everett, R.R.; Swain, F.E. (1947). 2605: 2521: 2312: 1337:systems used the same architecture. 615:. This is traditionally denoted as 471: 24: 4322:Annals of the History of Computing 4262:Annals of the History of Computing 4248: 4180:. January 24, 2013. Archived from 3885:qhn0qyveyu.fsf@ruckus.brouhaha.com 3191:from the original on June 12, 2010 2785:from the original on March 4, 2016 2577: 2201:When designing a new processor, a 1659:Microcode can be characterized as 1323:Internal Microprogrammed Interface 1229:The Digital Equipment Corporation 1073:University of California, Berkeley 299:Notable compilers & toolchains 25: 6581: 4546:Writable Instruction Set Computer 4472: 4318:"The Genesis of Microprogramming" 4297:Smotherman, Mark (October 2022). 4018:. Trends & News (in German). 4015:c't – magazin für computertechnik 3799:Spruth, Wilhelm (December 2012). 3376:Inside the AS/400, Second Edition 2723:IBM Technical Disclosure Bulletin 2229:There are counterpoints as well: 1996:) or from another processor in a 1927:writable instruction set computer 1913:A few computers were built using 1543: 1319:horizontal and vertical microcode 1153:to store its internal procedures. 1151:pegs inserted into rotating drums 1075:, that introduced the term RISC. 866: 666:Set the ALU's carry input to zero 376:of a computer, also known as its 30:For the CAD software vendor, see 6519:Semiconductor device fabrication 4572:Notes on Intel Microcode Updates 4481: 4070:by Paul Alcorn on March 15, 2018 3867:Smith, Eric (3 September 2002). 3856:from the original on 2008-05-11. 3332:Soltis, Frank (September 1981). 2752:Supnik, Bob (24 February 2008). 2486:. New York: Marcel Dekker, Inc. 2366: 2147: 2081: 1132:to implement some instructions. 896:enhanced this concept by adding 881:methods. The control store is a 787:complex instruction set computer 707: 629: 6494:History of general-purpose CPUs 4721:Nondeterministic Turing machine 4463:Shirriff, Ken (December 2022). 4217: 4188: 4166: 4155:from the original on 2008-02-23 4141: 4130:from the original on 2020-04-01 4116: 4098: 4073: 4061: 4037: 4026:from the original on 2017-08-28 3987: 3960: 3949:from the original on 2012-02-29 3927: 3903: 3860: 3831: 3792: 3756: 3726: 3699: 3669: 3644: 3618: 3607:from the original on 2020-03-24 3585: 3574:from the original on 2019-09-23 3552: 3541:from the original on 2019-09-23 3519: 3508:from the original on 2020-01-14 3486: 3456:Meynink, Todd (July 28, 2000). 3325: 3268: 3257:from the original on 2020-04-01 3203: 3177: 3154: 3096: 3056: 2956: 2936: 2893:. In Campbell-Kelly, M. (ed.). 2863: 2828: 2797: 2771: 2760:from the original on 2011-07-09 2744: 2733:from the original on 2012-10-01 2710: 2536:from the original on 2017-03-28 2449: 958:across the mainframe industry. 441:Some hardware vendors, notably 4674:Deterministic finite automaton 3802:The Design of a Microprocessor 3712:. KIT Scientific. p. 26. 2963:Starnes, Thomas (April 1983). 2687: 2664: 2640: 2599: 2547: 1108:to implement features such as 1037: 13: 1: 5465:Simultaneous and heterogenous 3771:Digital Equipment Corporation 3628:. AntiqueTech. Archived from 2897:. MIT Press. pp. 182–4. 2816:. 1967. p. 7. A22-6898-1 2706:. July 1986. EK-KA882-TD-PRE. 2704:Digital Equipment Corporation 2681:Digital Equipment Corporation 2462: 2299:network interface controllers 1858:on IBM mainframe processors. 1194:dedicated readers similar to 780:Digital Equipment Corporation 6149:Integrated memory controller 6131:Translation lookaside buffer 5330:Memory dependence prediction 4773:Random-access stored program 4726:Probabilistic Turing machine 3838:Koopman, Philip Jr. (1987). 3655:. McGraw-Hill. p. 300. 3403:. IGN64. November 10, 2000. 3161:Rogers, Bob (Sep–Oct 2012). 2587:Both, David (23 July 2020). 1969:Data General Eclipse MV/8000 1779:# previous microinstruction. 1317:is described as having both 1110:translation lookaside buffer 535: 374:instruction set architecture 256:target-specific initializer) 7: 5605:Synaptic updates per second 4556:Transformer Read-only Store 2946:VLSI VAX Micro-Architecture 2359: 2073:Comparison to VLIW and RISC 1372:Star Wars: Battle for Naboo 1135: 871:In 1947, the design of the 816: 609:static random-access memory 466: 83:Intermediate representation 32:MicroCode Engineering, Inc. 10: 6586: 6009:Heterogeneous architecture 4931:Orthogonal instruction set 4701:Alternating Turing machine 4689:Quantum cellular automaton 4255:Smith, Richard E. (1988). 2348:or unusual values such as 2225:for increased performance. 1963:implementations, some DEC 1906: 1610:, used to access the main 1510:Intel P6 microarchitecture 1392: 1028:orthogonal instruction set 916: 912: 861: 749:IBM Future Systems project 652:Connect register 7 to the 642:Connect register 1 to the 29: 6499:Microprocessor chronology 6486: 6462:Dynamic frequency scaling 6435: 6371: 6309: 6263: 6215: 6170: 6090: 6017: 5986: 5891: 5812: 5776: 5730: 5630: 5617:Cache performance metrics 5556: 5490: 5440: 5351: 5342: 5315: 5270: 5237: 5209: 5200: 5020: 4923: 4912: 4783: 4639: 4551:Capacitor Read-only Store 4391:10.1017/S0305004100028322 3468:United Business Media LLC 3080:10.1109/CMPCON.1990.63682 2522:Fog, Agner (2017-05-02). 2321:family starting with the 2309:, and in other hardware. 2307:graphics processing units 2287:digital signal processors 2156:This section needs to be 1976:Initial-Microprogram Load 1698:Arithmetic and logic unit 1596:arithmetic and logic unit 1581:general-purpose registers 1366:Star Wars: Rogue Squadron 1255:The Soul of a New Machine 1233:processor, KL10 and KS10 594: 513: 6514:Hardware security module 5857:Digital signal processor 5834:Graphics processing unit 5646:Graphics processing unit 4237:: CS1 maint: location ( 3373:Frank G. Soltis (1997). 3305:McGraw-Hill Book Company 2943:Supnik, Bob (May 1988). 2886:Wilkes, Maurice (1989). 2879:University of Manchester 2873:Wilkes, Maurice (1951). 2442: 2346:transcendental functions 2303:flash memory controllers 1885:cycles per instruction. 1854:on Alpha processors and 1715: 1650:programmable logic array 1514:AMD K7 microarchitecture 1489:, a cost-reduced PDP-11. 1452:Digital Scientific Corp. 1350:graphics processing unit 1026:. This offered a highly 795:programmable logic array 793:, is to use one or more 605:programmable logic array 6565:Central processing unit 6467:Dynamic voltage scaling 6250:Memory address register 6144:Branch target predictor 6108:Address generation unit 5851:Physics processing unit 5640:Central processing unit 5599:Transactions per second 5587:Instructions per second 5510:Array processing (SIMT) 4654:Stored-program computer 4334:10.1109/MAHC.1986.10035 4275:10.1109/MAHC.1988.10039 3706:Vaupel, Robert (2013). 3651:Hayes, John P. (1978). 3352:10.1109/C-M.1981.220610 2383:Address generation unit 1938:Burroughs Small Systems 1934:writable control stores 1604:memory address register 1030:with a wide variety of 659:Set the ALU to perform 370:central processing unit 307:GNU Compiler Collection 232:Common Language Runtime 6555:Instruction processing 6273:Hardwired control unit 6155:Memory management unit 6120:Memory management unit 5869:Secure cryptoprocessor 5863:Tensor Processing Unit 5845:Vision processing unit 5579:Cycles per instruction 5573:Instructions per cycle 5520:Associative processing 5211:Instruction pipelining 4633:Processor technologies 3877:alt.folklore.computers 3626:"Western Digital 1600" 3185:"EMIDEC 1100 computer" 1919:writable control store 1909:Writable control store 1903:Writable control store 1333:processor line, early 1013:backward compatibility 975: 900:, a concept akin to a 585:backward compatibility 398:hardwired control unit 162:Compilation strategies 6356:Sum-addressed decoder 6102:Arithmetic logic unit 5229:Classic RISC pipeline 5183:Epiphany architecture 5030:Motorola 68000 series 4436:Tucker, S.G. (1967). 4413:Husson, S.S. (1970). 4184:on September 1, 2014. 3433:. December 12, 2000. 3070:. San Francisco, CA: 3042:10.1145/641914.641918 969: 898:conditional execution 768:instruction fetches. 757:memory block transfer 691:Microjump to a given 478:arithmetic logic unit 453:interchangeably with 400:is unable to manage. 187:Compile and go system 6477:Performance per watt 6055:replacement policies 5721:Package on a package 5611:Performance per watt 5515:Pipelined processing 5285:Tomasulo's algorithm 5090:Clipper architecture 4946:Application-specific 4659:Finite-state machine 4502:improve this article 4010:"Prozessorgeflüster" 3739:IBM Systems Magazine 3167:IBM Systems Magazine 2952:. Digital Equipment. 2877:(Technical report). 2416:Instruction pipeline 2394:Finite-state machine 2105:improve this section 2063:Varian Data Machines 1694:Destination register 1675:Horizontal microcode 1608:memory data register 1602:There may also be a 1570:instruction register 1399:Nintendo 64 Game Pak 1265:are microprogrammed: 1246:Data General Eclipse 589:electronic circuitry 497:programming language 434:lengths, additional 382:finite-state machine 260:Java virtual machine 182:Tracing just-in-time 6509:Digital electronics 6162:Instruction decoder 6114:Floating-point unit 5768:Soft microprocessor 5715:System in a package 5290:Reservation station 4820:Transport-triggered 4514:footnote references 4443:IBM Systems Journal 4383:1953PCPS...49..230W 4205:. Texas Instruments 3281:Daniel P. Siewiorek 3173:on October 9, 2012. 3136:(Second ed.). 3008:10.1147/rd.341.0004 2930:Ken Shirriff's blog 2634:Ken Shirriff's blog 2608:"NMOS 6502 Opcodes" 2405:Floating-point unit 2343:floating-point unit 2291:channel controllers 2021:CPUs have writable 1669:combinatorial logic 1498:patchable microcode 1414:The MicroCore Labs 1346:Reality Coprocessor 1120:architecture. CMOS 985:integrated circuits 947:floating point unit 836:System/360 Model 40 828:System/360 Model 30 809:-level simulation. 803:MOS Technology 6502 724:and rather minimal 722:combinational logic 384:sequencing in many 76:Optimizing compiler 6381:Integrated circuit 6225:Processor register 5879:Baseband processor 5224:Operand forwarding 4684:Cellular automaton 4456:10.1147/sj.64.0222 4377:(pt. 2): 230–238. 3910:Smotherman, Mark. 2374:Electronics portal 2283:network processors 2013:Starting with the 1967:machines, and the 1944:workstations, the 1915:writable microcode 1830:Vertical microcode 1806:InstructionDecode 1476:Pascal MicroEngine 1443:2018-12-21 at the 1432:2017-02-02 at the 1421:2016-11-03 at the 1379:playback found in 1261:Many systems from 989:superminicomputers 976: 962:Moving up the line 765:multi-level caches 424:microarchitectures 386:digital processing 6542: 6541: 6431: 6430: 6050:Instruction cache 6040:Scratchpad memory 5887: 5886: 5874:Network processor 5803:Network on a chip 5758:Ultra-low-voltage 5709:Multi-chip module 5552: 5551: 5338: 5337: 5325:Branch prediction 5302:Register renaming 5196: 5195: 5178:VISC architecture 5000:Quantum computing 4995:VISC architecture 4877:Secondary storage 4793:Microarchitecture 4753:Register machines 4542: 4541: 4534: 4421:. Prentice-Hall. 4057:. September 2016. 3812:978-3-642-74916-2 3719:978-3-7315-0022-3 3632:on 3 January 2017 3187:. Emidec.org.uk. 2904:978-0-262-23136-7 2565:on April 19, 2019 2203:hardwired control 2192:interrupt latency 2177: 2176: 2141: 2140: 2133: 2017:in 1995, several 1874: 1873: 1724:# memory address. 1710: 1709: 1691:Register source B 1688:Register source A 1377:full motion video 1327:Machine Interface 1143:Analytical engine 741:assembly language 624:read–write memory 581:assembly language 358: 357: 40:Program execution 16:(Redirected from 6577: 6504:Processor design 6396:Power management 6278:Instruction unit 6139:Branch predictor 6088: 6087: 5786:System on a chip 5728: 5727: 5568:Transistor count 5492:Flynn's taxonomy 5349: 5348: 5207: 5206: 5010:Addressing modes 4921: 4920: 4867:Memory hierarchy 4731:Hypercomputation 4649:Abstract machine 4626: 4619: 4612: 4603: 4602: 4537: 4530: 4526: 4523: 4517: 4485: 4484: 4477: 4468: 4459: 4432: 4420: 4409: 4407: 4405: 4352: 4350: 4348: 4309: 4307: 4305: 4293: 4291: 4289: 4243: 4242: 4236: 4228: 4221: 4215: 4214: 4212: 4210: 4200: 4192: 4186: 4185: 4170: 4164: 4163: 4161: 4160: 4145: 4139: 4138: 4136: 4135: 4120: 4114: 4113: 4108:. Archived from 4102: 4096: 4095: 4093: 4092: 4083:. Archived from 4077: 4071: 4065: 4059: 4058: 4052: 4041: 4035: 4034: 4032: 4031: 4005: 3999: 3998: 3991: 3985: 3984: 3982: 3980: 3974: 3964: 3958: 3957: 3955: 3954: 3948: 3941: 3931: 3925: 3924: 3919: 3918: 3907: 3901: 3900: 3898: 3896: 3864: 3858: 3857: 3855: 3844: 3835: 3829: 3828: 3826: 3824: 3796: 3790: 3789: 3787: 3785: 3779: 3768: 3760: 3754: 3753: 3751: 3750: 3741:. Archived from 3730: 3724: 3723: 3703: 3697: 3696: 3694: 3693: 3684:. Archived from 3673: 3667: 3666: 3648: 3642: 3641: 3639: 3637: 3622: 3616: 3615: 3613: 3612: 3606: 3599: 3589: 3583: 3582: 3580: 3579: 3573: 3566: 3556: 3550: 3549: 3547: 3546: 3540: 3533: 3523: 3517: 3516: 3514: 3513: 3507: 3500: 3490: 3484: 3483: 3481: 3479: 3453: 3447: 3446: 3444: 3442: 3423: 3417: 3416: 3414: 3412: 3397: 3391: 3390: 3370: 3364: 3363: 3329: 3323: 3322: 3298: 3272: 3266: 3265: 3263: 3262: 3256: 3249: 3239: 3228: 3227: 3225: 3223: 3217: 3207: 3201: 3200: 3198: 3196: 3181: 3175: 3174: 3169:. Archived from 3158: 3152: 3151: 3135: 3124: 3115: 3114: 3113:. November 1995. 3108: 3100: 3094: 3093: 3060: 3054: 3053: 3021: 3012: 3011: 2993: 2984: 2973: 2972: 2960: 2954: 2953: 2951: 2940: 2934: 2933: 2921: 2912: 2908: 2892: 2882: 2867: 2861: 2860: 2858: 2856: 2851:on June 17, 2012 2850: 2843: 2832: 2826: 2825: 2823: 2821: 2811: 2801: 2795: 2794: 2792: 2790: 2775: 2769: 2768: 2766: 2765: 2748: 2742: 2741: 2739: 2738: 2714: 2708: 2707: 2701: 2691: 2685: 2684: 2678: 2668: 2662: 2661: 2659: 2658: 2644: 2638: 2637: 2625: 2616: 2615: 2603: 2597: 2596: 2584: 2575: 2574: 2572: 2570: 2561:. Archived from 2551: 2545: 2544: 2542: 2541: 2535: 2528: 2519: 2510: 2509: 2507: 2505: 2477: 2456: 2453: 2411:Pentium FDIV bug 2376: 2371: 2370: 2350:denormal numbers 2335:micro-operations 2313:Micro-operations 2295:disk controllers 2172: 2169: 2163: 2151: 2150: 2143: 2136: 2129: 2125: 2122: 2116: 2085: 2077: 1864: 1863: 1821: 1818: 1815: 1812: 1809: 1805: 1801: 1797: 1793: 1790: 1787: 1783: 1780: 1777: 1774: 1770: 1766: 1762: 1758: 1754: 1750: 1747: 1744: 1741: 1738: 1735: 1732: 1729: 1725: 1722: 1719: 1685: 1684: 1654:read-only memory 1612:computer storage 1539:of a video card. 1506:operating system 1237:processors, and 1047:, a team led by 1045:telephone switch 1032:addressing modes 907:microprogramming 799:read-only memory 761:memory pre-fetch 714:instruction sets 661:two's-complement 601:read-only memory 515: 472:Instruction sets 413:microprogramming 362:processor design 350: 343: 336: 212:Notable runtimes 199:Transcompilation 46:General concepts 36: 35: 21: 18:Microprogramming 6585: 6584: 6580: 6579: 6578: 6576: 6575: 6574: 6545: 6544: 6543: 6538: 6524:Tick–tock model 6482: 6438: 6427: 6367: 6351:Address decoder 6305: 6259: 6255:Program counter 6230:Status register 6211: 6166: 6126:Load–store unit 6093: 6086: 6013: 5982: 5883: 5840:Image processor 5815: 5808: 5778: 5772: 5748:Microcontroller 5738:Embedded system 5726: 5626: 5559: 5548: 5486: 5436: 5334: 5311: 5295:Re-order buffer 5266: 5247:Data dependency 5233: 5192: 5022: 5016: 4915: 4914:Instruction set 4908: 4894:Multiprocessing 4862:Cache hierarchy 4855:Register/memory 4779: 4679:Queue automaton 4635: 4630: 4598:, July 26, 2022 4592:, July 26, 2004 4538: 4527: 4521: 4518: 4499: 4490:This article's 4486: 4482: 4475: 4429: 4403: 4401: 4361:Stringer, J. B. 4346: 4344: 4303: 4301: 4287: 4285: 4251: 4249:Further reading 4246: 4230: 4229: 4223: 4222: 4218: 4208: 4206: 4198: 4194: 4193: 4189: 4172: 4171: 4167: 4158: 4156: 4147: 4146: 4142: 4133: 4131: 4126:. Freebsd.org. 4122: 4121: 4117: 4104: 4103: 4099: 4090: 4088: 4079: 4078: 4074: 4066: 4062: 4050: 4043: 4042: 4038: 4029: 4027: 4006: 4002: 3993: 3992: 3988: 3978: 3976: 3972: 3966: 3965: 3961: 3952: 3950: 3946: 3939: 3933: 3932: 3928: 3916: 3914: 3908: 3904: 3894: 3892: 3865: 3861: 3853: 3842: 3836: 3832: 3822: 3820: 3813: 3797: 3793: 3783: 3781: 3777: 3766: 3762: 3761: 3757: 3748: 3746: 3731: 3727: 3720: 3704: 3700: 3691: 3689: 3674: 3670: 3663: 3649: 3645: 3635: 3633: 3624: 3623: 3619: 3610: 3608: 3604: 3597: 3591: 3590: 3586: 3577: 3575: 3571: 3564: 3558: 3557: 3553: 3544: 3542: 3538: 3531: 3525: 3524: 3520: 3511: 3509: 3505: 3498: 3492: 3491: 3487: 3477: 3475: 3454: 3450: 3440: 3438: 3425: 3424: 3420: 3410: 3408: 3399: 3398: 3394: 3387: 3371: 3367: 3330: 3326: 3319: 3273: 3269: 3260: 3258: 3254: 3247: 3241: 3240: 3231: 3221: 3219: 3215: 3209: 3208: 3204: 3194: 3192: 3183: 3182: 3178: 3159: 3155: 3148: 3133: 3126: 3125: 3118: 3106: 3102: 3101: 3097: 3090: 3062: 3061: 3057: 3022: 3015: 2991: 2985: 2976: 2961: 2957: 2949: 2941: 2937: 2924:Shirriff, Ken. 2922: 2915: 2911: 2905: 2890: 2868: 2864: 2854: 2852: 2848: 2841: 2833: 2829: 2819: 2817: 2809: 2803: 2802: 2798: 2788: 2786: 2777: 2776: 2772: 2763: 2761: 2749: 2745: 2736: 2734: 2715: 2711: 2699: 2693: 2692: 2688: 2676: 2670: 2669: 2665: 2656: 2654: 2646: 2645: 2641: 2628:Shirriff, Ken. 2626: 2619: 2606:Pickens, John. 2604: 2600: 2585: 2578: 2568: 2566: 2553: 2552: 2548: 2539: 2537: 2533: 2526: 2520: 2513: 2503: 2501: 2494: 2478: 2469: 2465: 2460: 2459: 2454: 2450: 2445: 2440: 2372: 2365: 2362: 2315: 2173: 2167: 2164: 2161: 2152: 2148: 2137: 2126: 2120: 2117: 2102: 2086: 2075: 2023:Intel Microcode 1998:tightly coupled 1911: 1905: 1832: 1823: 1822: 1819: 1816: 1813: 1810: 1807: 1803: 1799: 1795: 1791: 1788: 1785: 1781: 1778: 1775: 1772: 1768: 1764: 1760: 1756: 1752: 1748: 1745: 1742: 1739: 1736: 1733: 1730: 1727: 1726:InstructionJUMP 1723: 1720: 1717: 1677: 1618:". Most modern 1585:program counter 1546: 1535:, for example, 1472:Western Digital 1445:Wayback Machine 1434:Wayback Machine 1423:Wayback Machine 1401: 1386:Resident Evil 2 1250:Eclipse MV/8000 1147:Charles Babbage 1138: 1040: 1004:microprocessors 964: 921: 915: 869: 864: 819: 791:microprocessors 710: 656:side of the ALU 632: 597: 538: 474: 469: 461:hard disk drive 449:, use the term 436:execution units 354: 234:(CLR) and 220:Android Runtime 116:Virtual machine 34: 28: 23: 22: 15: 12: 11: 5: 6583: 6573: 6572: 6567: 6562: 6557: 6540: 6539: 6537: 6536: 6531: 6529:Pin grid array 6526: 6521: 6516: 6511: 6506: 6501: 6496: 6490: 6488: 6484: 6483: 6481: 6480: 6474: 6469: 6464: 6459: 6454: 6449: 6443: 6441: 6433: 6432: 6429: 6428: 6426: 6425: 6420: 6415: 6410: 6405: 6400: 6399: 6398: 6393: 6388: 6377: 6375: 6369: 6368: 6366: 6365: 6363:Barrel shifter 6360: 6359: 6358: 6353: 6346:Binary decoder 6343: 6342: 6341: 6331: 6326: 6321: 6315: 6313: 6307: 6306: 6304: 6303: 6298: 6290: 6285: 6280: 6275: 6269: 6267: 6261: 6260: 6258: 6257: 6252: 6247: 6242: 6237: 6235:Stack register 6232: 6227: 6221: 6219: 6213: 6212: 6210: 6209: 6208: 6207: 6202: 6192: 6187: 6182: 6176: 6174: 6168: 6167: 6165: 6164: 6159: 6158: 6157: 6146: 6141: 6136: 6135: 6134: 6128: 6117: 6111: 6105: 6098: 6096: 6085: 6084: 6079: 6074: 6069: 6064: 6063: 6062: 6057: 6052: 6047: 6042: 6037: 6027: 6021: 6019: 6015: 6014: 6012: 6011: 6006: 6001: 5996: 5990: 5988: 5984: 5983: 5981: 5980: 5979: 5978: 5968: 5963: 5958: 5953: 5948: 5943: 5938: 5933: 5928: 5923: 5918: 5913: 5908: 5903: 5897: 5895: 5889: 5888: 5885: 5884: 5882: 5881: 5876: 5871: 5866: 5860: 5854: 5848: 5842: 5837: 5831: 5829:AI accelerator 5826: 5820: 5818: 5810: 5809: 5807: 5806: 5800: 5795: 5792:Multiprocessor 5789: 5782: 5780: 5774: 5773: 5771: 5770: 5765: 5760: 5755: 5750: 5745: 5743:Microprocessor 5740: 5734: 5732: 5731:By application 5725: 5724: 5718: 5712: 5706: 5701: 5696: 5691: 5686: 5681: 5676: 5674:Tile processor 5671: 5666: 5661: 5656: 5655: 5654: 5643: 5636: 5634: 5628: 5627: 5625: 5624: 5619: 5614: 5608: 5602: 5596: 5590: 5584: 5583: 5582: 5570: 5564: 5562: 5554: 5553: 5550: 5549: 5547: 5546: 5545: 5544: 5534: 5529: 5528: 5527: 5522: 5517: 5512: 5502: 5496: 5494: 5488: 5487: 5485: 5484: 5479: 5474: 5469: 5468: 5467: 5462: 5460:Hyperthreading 5452: 5446: 5444: 5442:Multithreading 5438: 5437: 5435: 5434: 5429: 5424: 5423: 5422: 5412: 5411: 5410: 5405: 5395: 5394: 5393: 5388: 5378: 5373: 5372: 5371: 5366: 5355: 5353: 5346: 5340: 5339: 5336: 5335: 5333: 5332: 5327: 5321: 5319: 5313: 5312: 5310: 5309: 5304: 5299: 5298: 5297: 5292: 5282: 5276: 5274: 5268: 5267: 5265: 5264: 5259: 5254: 5249: 5243: 5241: 5235: 5234: 5232: 5231: 5226: 5221: 5219:Pipeline stall 5215: 5213: 5204: 5198: 5197: 5194: 5193: 5191: 5190: 5185: 5180: 5175: 5172: 5171: 5170: 5168:z/Architecture 5165: 5160: 5155: 5147: 5142: 5137: 5132: 5127: 5122: 5117: 5112: 5107: 5102: 5097: 5092: 5087: 5086: 5085: 5080: 5075: 5067: 5062: 5057: 5052: 5047: 5042: 5037: 5032: 5026: 5024: 5018: 5017: 5015: 5014: 5013: 5012: 5002: 4997: 4992: 4987: 4982: 4977: 4972: 4971: 4970: 4960: 4959: 4958: 4948: 4943: 4938: 4933: 4927: 4925: 4918: 4910: 4909: 4907: 4906: 4901: 4896: 4891: 4886: 4881: 4880: 4879: 4874: 4872:Virtual memory 4864: 4859: 4858: 4857: 4852: 4847: 4842: 4832: 4827: 4822: 4817: 4812: 4811: 4810: 4800: 4795: 4789: 4787: 4781: 4780: 4778: 4777: 4776: 4775: 4770: 4765: 4760: 4750: 4745: 4740: 4739: 4738: 4733: 4728: 4723: 4718: 4713: 4708: 4703: 4696:Turing machine 4693: 4692: 4691: 4686: 4681: 4676: 4671: 4666: 4656: 4651: 4645: 4643: 4637: 4636: 4629: 4628: 4621: 4614: 4606: 4600: 4599: 4593: 4587: 4575: 4569: 4563: 4558: 4553: 4548: 4540: 4539: 4494:external links 4489: 4487: 4480: 4474: 4473:External links 4471: 4470: 4469: 4460: 4450:(4): 222–241. 4433: 4427: 4410: 4363:(April 1953). 4353: 4328:(2): 116–126. 4310: 4294: 4269:(4): 277–303. 4250: 4247: 4245: 4244: 4216: 4187: 4165: 4140: 4115: 4112:on 2012-02-26. 4097: 4072: 4060: 4036: 4000: 3986: 3959: 3926: 3902: 3859: 3830: 3811: 3791: 3755: 3725: 3718: 3698: 3668: 3661: 3643: 3617: 3584: 3551: 3518: 3485: 3448: 3418: 3392: 3386:978-1882419661 3385: 3379:. Duke Press. 3365: 3324: 3317: 3285:C. Gordon Bell 3267: 3229: 3202: 3176: 3153: 3146: 3116: 3095: 3088: 3055: 3013: 2974: 2955: 2935: 2913: 2910: 2909: 2903: 2883: 2869: 2862: 2827: 2796: 2770: 2743: 2709: 2686: 2663: 2639: 2617: 2598: 2576: 2546: 2511: 2492: 2466: 2464: 2461: 2458: 2457: 2447: 2446: 2444: 2441: 2439: 2438: 2433: 2428: 2423: 2421:Microsequencer 2418: 2413: 2408: 2402: 2397: 2391: 2386: 2379: 2378: 2377: 2361: 2358: 2314: 2311: 2273:Many RISC and 2271: 2270: 2266: 2263:Motorola 68040 2243: 2227: 2226: 2219: 2216: 2213: 2210: 2175: 2174: 2155: 2153: 2146: 2139: 2138: 2089: 2087: 2080: 2074: 2071: 2001:multiprocessor 1989:power-on reset 1955:) family, the 1907:Main article: 1904: 1901: 1872: 1871: 1868: 1848:z/Architecture 1831: 1828: 1716: 1708: 1707: 1704: 1701: 1695: 1692: 1689: 1676: 1673: 1640:microassembler 1616:execution unit 1600: 1599: 1592: 1573: 1566:microsequencer 1562: 1545: 1544:Implementation 1542: 1541: 1540: 1517: 1490: 1468:microprocessor 1460: 1448: 1412: 1391: 1390: 1338: 1311: 1304: 1293: 1292: 1291: 1290: 1274: 1267: 1266: 1259: 1242: 1227: 1216: 1215: 1214: 1206: 1199: 1184: 1176: 1161: 1154: 1145:envisioned by 1137: 1134: 1126:z/Architecture 1122:IBM System/390 1039: 1036: 1024:Motorola 68000 972:Motorola 68000 963: 960: 936:in their 1964 917:Main article: 914: 911: 894:Maurice Wilkes 868: 867:Early examples 865: 863: 860: 856:hardware logic 818: 815: 709: 706: 697: 696: 689: 670: 667: 664: 657: 650: 631: 628: 596: 593: 537: 534: 473: 470: 468: 465: 356: 355: 353: 352: 345: 338: 330: 327: 326: 325: 324: 319: 310: 301: 300: 296: 295: 294: 293: 287: 278: 268: 263: 257: 247: 238: 229: 223: 214: 213: 209: 208: 207: 206: 201: 196: 194:Precompilation 191: 190: 189: 184: 173: 164: 163: 159: 158: 157: 156: 151: 146: 141: 136: 128: 127: 123: 122: 121: 120: 119: 118: 113: 108: 103: 102: 101: 94:Runtime system 86: 80: 79: 78: 73: 72: 71: 56: 48: 47: 43: 42: 26: 9: 6: 4: 3: 2: 6582: 6571: 6568: 6566: 6563: 6561: 6558: 6556: 6553: 6552: 6550: 6535: 6532: 6530: 6527: 6525: 6522: 6520: 6517: 6515: 6512: 6510: 6507: 6505: 6502: 6500: 6497: 6495: 6492: 6491: 6489: 6485: 6478: 6475: 6473: 6470: 6468: 6465: 6463: 6460: 6458: 6455: 6453: 6450: 6448: 6445: 6444: 6442: 6440: 6434: 6424: 6421: 6419: 6416: 6414: 6411: 6409: 6406: 6404: 6401: 6397: 6394: 6392: 6389: 6387: 6384: 6383: 6382: 6379: 6378: 6376: 6374: 6370: 6364: 6361: 6357: 6354: 6352: 6349: 6348: 6347: 6344: 6340: 6337: 6336: 6335: 6332: 6330: 6327: 6325: 6324:Demultiplexer 6322: 6320: 6317: 6316: 6314: 6312: 6308: 6302: 6299: 6297: 6294: 6291: 6289: 6286: 6284: 6281: 6279: 6276: 6274: 6271: 6270: 6268: 6266: 6262: 6256: 6253: 6251: 6248: 6246: 6245:Memory buffer 6243: 6241: 6240:Register file 6238: 6236: 6233: 6231: 6228: 6226: 6223: 6222: 6220: 6218: 6214: 6206: 6203: 6201: 6198: 6197: 6196: 6193: 6191: 6188: 6186: 6183: 6181: 6180:Combinational 6178: 6177: 6175: 6173: 6169: 6163: 6160: 6156: 6153: 6152: 6150: 6147: 6145: 6142: 6140: 6137: 6132: 6129: 6127: 6124: 6123: 6121: 6118: 6115: 6112: 6109: 6106: 6103: 6100: 6099: 6097: 6095: 6089: 6083: 6080: 6078: 6075: 6073: 6070: 6068: 6065: 6061: 6058: 6056: 6053: 6051: 6048: 6046: 6043: 6041: 6038: 6036: 6033: 6032: 6031: 6028: 6026: 6023: 6022: 6020: 6016: 6010: 6007: 6005: 6002: 6000: 5997: 5995: 5992: 5991: 5989: 5985: 5977: 5974: 5973: 5972: 5969: 5967: 5964: 5962: 5959: 5957: 5954: 5952: 5949: 5947: 5944: 5942: 5939: 5937: 5934: 5932: 5929: 5927: 5924: 5922: 5919: 5917: 5914: 5912: 5909: 5907: 5904: 5902: 5899: 5898: 5896: 5894: 5890: 5880: 5877: 5875: 5872: 5870: 5867: 5864: 5861: 5858: 5855: 5852: 5849: 5846: 5843: 5841: 5838: 5835: 5832: 5830: 5827: 5825: 5822: 5821: 5819: 5817: 5811: 5804: 5801: 5799: 5796: 5793: 5790: 5787: 5784: 5783: 5781: 5775: 5769: 5766: 5764: 5761: 5759: 5756: 5754: 5751: 5749: 5746: 5744: 5741: 5739: 5736: 5735: 5733: 5729: 5722: 5719: 5716: 5713: 5710: 5707: 5705: 5702: 5700: 5697: 5695: 5692: 5690: 5687: 5685: 5682: 5680: 5677: 5675: 5672: 5670: 5667: 5665: 5662: 5660: 5657: 5653: 5650: 5649: 5647: 5644: 5641: 5638: 5637: 5635: 5633: 5629: 5623: 5620: 5618: 5615: 5612: 5609: 5606: 5603: 5600: 5597: 5594: 5591: 5588: 5585: 5580: 5577: 5576: 5574: 5571: 5569: 5566: 5565: 5563: 5561: 5555: 5543: 5540: 5539: 5538: 5535: 5533: 5530: 5526: 5523: 5521: 5518: 5516: 5513: 5511: 5508: 5507: 5506: 5503: 5501: 5498: 5497: 5495: 5493: 5489: 5483: 5480: 5478: 5475: 5473: 5470: 5466: 5463: 5461: 5458: 5457: 5456: 5453: 5451: 5448: 5447: 5445: 5443: 5439: 5433: 5430: 5428: 5425: 5421: 5418: 5417: 5416: 5413: 5409: 5406: 5404: 5401: 5400: 5399: 5396: 5392: 5389: 5387: 5384: 5383: 5382: 5379: 5377: 5374: 5370: 5367: 5365: 5362: 5361: 5360: 5357: 5356: 5354: 5350: 5347: 5345: 5341: 5331: 5328: 5326: 5323: 5322: 5320: 5318: 5314: 5308: 5305: 5303: 5300: 5296: 5293: 5291: 5288: 5287: 5286: 5283: 5281: 5280:Scoreboarding 5278: 5277: 5275: 5273: 5269: 5263: 5262:False sharing 5260: 5258: 5255: 5253: 5250: 5248: 5245: 5244: 5242: 5240: 5236: 5230: 5227: 5225: 5222: 5220: 5217: 5216: 5214: 5212: 5208: 5205: 5203: 5199: 5189: 5186: 5184: 5181: 5179: 5176: 5173: 5169: 5166: 5164: 5161: 5159: 5156: 5154: 5151: 5150: 5148: 5146: 5143: 5141: 5138: 5136: 5133: 5131: 5128: 5126: 5123: 5121: 5118: 5116: 5113: 5111: 5108: 5106: 5103: 5101: 5098: 5096: 5093: 5091: 5088: 5084: 5081: 5079: 5076: 5074: 5071: 5070: 5068: 5066: 5063: 5061: 5058: 5056: 5055:Stanford MIPS 5053: 5051: 5048: 5046: 5043: 5041: 5038: 5036: 5033: 5031: 5028: 5027: 5025: 5019: 5011: 5008: 5007: 5006: 5003: 5001: 4998: 4996: 4993: 4991: 4988: 4986: 4983: 4981: 4978: 4976: 4973: 4969: 4966: 4965: 4964: 4961: 4957: 4954: 4953: 4952: 4949: 4947: 4944: 4942: 4939: 4937: 4934: 4932: 4929: 4928: 4926: 4922: 4919: 4917: 4916:architectures 4911: 4905: 4902: 4900: 4897: 4895: 4892: 4890: 4887: 4885: 4884:Heterogeneous 4882: 4878: 4875: 4873: 4870: 4869: 4868: 4865: 4863: 4860: 4856: 4853: 4851: 4848: 4846: 4843: 4841: 4838: 4837: 4836: 4835:Memory access 4833: 4831: 4828: 4826: 4823: 4821: 4818: 4816: 4813: 4809: 4806: 4805: 4804: 4801: 4799: 4796: 4794: 4791: 4790: 4788: 4786: 4782: 4774: 4771: 4769: 4768:Random-access 4766: 4764: 4761: 4759: 4756: 4755: 4754: 4751: 4749: 4748:Stack machine 4746: 4744: 4741: 4737: 4734: 4732: 4729: 4727: 4724: 4722: 4719: 4717: 4714: 4712: 4709: 4707: 4704: 4702: 4699: 4698: 4697: 4694: 4690: 4687: 4685: 4682: 4680: 4677: 4675: 4672: 4670: 4667: 4665: 4664:with datapath 4662: 4661: 4660: 4657: 4655: 4652: 4650: 4647: 4646: 4644: 4642: 4638: 4634: 4627: 4622: 4620: 4615: 4613: 4608: 4607: 4604: 4597: 4594: 4591: 4588: 4585: 4584: 4579: 4576: 4573: 4570: 4567: 4564: 4562: 4559: 4557: 4554: 4552: 4549: 4547: 4544: 4543: 4536: 4533: 4525: 4522:February 2017 4515: 4511: 4510:inappropriate 4507: 4503: 4497: 4495: 4488: 4479: 4478: 4466: 4461: 4457: 4453: 4449: 4445: 4444: 4439: 4434: 4430: 4428:0-13-581454-5 4424: 4419: 4418: 4411: 4400: 4396: 4392: 4388: 4384: 4380: 4376: 4372: 4371: 4366: 4362: 4358: 4357:Wilkes, M. V. 4354: 4343: 4339: 4335: 4331: 4327: 4323: 4319: 4315: 4314:Wilkes, M. V. 4311: 4300: 4295: 4284: 4280: 4276: 4272: 4268: 4264: 4263: 4258: 4253: 4252: 4240: 4234: 4226: 4220: 4204: 4203:Bitsavers.org 4197: 4191: 4183: 4179: 4175: 4169: 4154: 4150: 4144: 4129: 4125: 4119: 4111: 4107: 4101: 4087:on 2018-03-19 4086: 4082: 4076: 4069: 4064: 4056: 4049: 4048: 4040: 4025: 4021: 4017: 4016: 4011: 4004: 3996: 3990: 3971: 3970: 3963: 3945: 3938: 3937: 3930: 3923: 3913: 3906: 3890: 3886: 3882: 3878: 3874: 3870: 3863: 3852: 3848: 3841: 3834: 3818: 3814: 3808: 3804: 3803: 3795: 3776: 3772: 3765: 3759: 3745:on 2013-10-16 3744: 3740: 3736: 3729: 3721: 3715: 3711: 3710: 3702: 3688:on 2015-04-19 3687: 3683: 3679: 3672: 3664: 3662:0-07-027363-4 3658: 3654: 3647: 3631: 3627: 3621: 3603: 3596: 3595: 3588: 3570: 3563: 3562: 3555: 3537: 3530: 3529: 3522: 3504: 3497: 3496: 3489: 3473: 3469: 3465: 3464: 3459: 3452: 3441:September 24, 3436: 3432: 3428: 3422: 3406: 3402: 3396: 3388: 3382: 3378: 3377: 3369: 3361: 3357: 3353: 3349: 3345: 3341: 3340: 3339:IEEE Computer 3335: 3328: 3320: 3318:0-07-057302-6 3314: 3310: 3306: 3302: 3297: 3296: 3290: 3286: 3282: 3278: 3271: 3253: 3246: 3245: 3238: 3236: 3234: 3214: 3213: 3206: 3190: 3186: 3180: 3172: 3168: 3164: 3157: 3149: 3147:1-55558-145-5 3143: 3139: 3138:Digital Press 3132: 3131: 3123: 3121: 3112: 3109:(Datasheet). 3105: 3099: 3091: 3089:0-8186-2028-5 3085: 3081: 3077: 3073: 3069: 3065: 3059: 3051: 3047: 3043: 3039: 3035: 3031: 3027: 3020: 3018: 3009: 3005: 3001: 2997: 2990: 2983: 2981: 2979: 2970: 2966: 2959: 2948: 2947: 2939: 2931: 2927: 2920: 2918: 2906: 2900: 2896: 2889: 2884: 2880: 2876: 2871: 2870: 2866: 2847: 2840: 2839: 2831: 2815: 2808: 2807: 2800: 2784: 2780: 2779:"6502 Images" 2774: 2759: 2755: 2747: 2732: 2728: 2724: 2720: 2713: 2705: 2698: 2697: 2690: 2682: 2675: 2674: 2667: 2653: 2649: 2643: 2635: 2631: 2624: 2622: 2613: 2609: 2602: 2594: 2590: 2583: 2581: 2564: 2560: 2556: 2550: 2532: 2525: 2518: 2516: 2499: 2495: 2493:0-8247-2281-7 2489: 2485: 2484: 2476: 2474: 2472: 2467: 2452: 2448: 2437: 2434: 2432: 2429: 2427: 2424: 2422: 2419: 2417: 2414: 2412: 2409: 2406: 2403: 2401: 2398: 2395: 2392: 2390: 2387: 2384: 2381: 2380: 2375: 2369: 2364: 2357: 2355: 2351: 2347: 2344: 2339: 2336: 2332: 2328: 2325:Nx586, Intel 2324: 2320: 2310: 2308: 2304: 2300: 2296: 2292: 2288: 2284: 2279: 2276: 2267: 2264: 2260: 2256: 2252: 2248: 2244: 2242:, and others. 2241: 2237: 2232: 2231: 2230: 2224: 2220: 2217: 2214: 2211: 2208: 2207: 2206: 2204: 2199: 2197: 2193: 2189: 2184: 2182: 2171: 2168:December 2023 2159: 2154: 2145: 2144: 2135: 2132: 2124: 2114: 2110: 2106: 2100: 2099: 2095: 2090:This section 2088: 2084: 2079: 2078: 2070: 2068: 2067:minicomputers 2064: 2060: 2056: 2052: 2047: 2045: 2041: 2037: 2032: 2028: 2024: 2020: 2016: 2011: 2007: 2004: 2002: 1999: 1995: 1991: 1990: 1985: 1981: 1977: 1972: 1970: 1966: 1962: 1958: 1954: 1950: 1947: 1943: 1939: 1935: 1930: 1928: 1924: 1920: 1916: 1910: 1900: 1898: 1894: 1889: 1886: 1883: 1879: 1869: 1866: 1865: 1862: 1859: 1857: 1853: 1849: 1845: 1841: 1836: 1827: 1714: 1706:Jump address 1705: 1702: 1699: 1696: 1693: 1690: 1687: 1686: 1683: 1680: 1672: 1670: 1666: 1662: 1657: 1655: 1651: 1646: 1641: 1636: 1634: 1630: 1627:" chips. The 1626: 1621: 1617: 1613: 1609: 1605: 1597: 1593: 1590: 1589:register file 1586: 1582: 1578: 1574: 1571: 1567: 1563: 1560: 1556: 1552: 1551: 1550: 1538: 1534: 1530: 1526: 1522: 1518: 1515: 1511: 1507: 1503: 1499: 1495: 1491: 1488: 1485: 1481: 1477: 1473: 1469: 1465: 1461: 1458: 1453: 1449: 1446: 1442: 1439: 1435: 1431: 1428: 1424: 1420: 1417: 1413: 1410: 1409:PlayStation 2 1407: 1403: 1402: 1400: 1396: 1388: 1387: 1382: 1381:Angel Studios 1378: 1374: 1373: 1368: 1367: 1362: 1361: 1356: 1351: 1347: 1343: 1339: 1336: 1332: 1328: 1324: 1320: 1316: 1315:IBM System/38 1312: 1309: 1305: 1302: 1298: 1295: 1294: 1288: 1284: 1279: 1275: 1271: 1270: 1269: 1268: 1264: 1260: 1257: 1256: 1251: 1247: 1243: 1240: 1236: 1232: 1228: 1225: 1221: 1217: 1211: 1207: 1204: 1200: 1197: 1193: 1189: 1185: 1181: 1177: 1174: 1169: 1165: 1164: 1162: 1159: 1155: 1152: 1148: 1144: 1140: 1139: 1133: 1131: 1127: 1123: 1119: 1115: 1111: 1107: 1101: 1099: 1095: 1090: 1086: 1080: 1076: 1074: 1069: 1064: 1061: 1058: 1054: 1050: 1046: 1035: 1033: 1029: 1025: 1020: 1018: 1014: 1009: 1005: 1000: 998: 994: 990: 986: 981: 980:minicomputers 973: 968: 959: 957: 951: 948: 942: 939: 935: 931: 927: 920: 910: 908: 903: 899: 895: 890: 888: 884: 880: 879: 874: 873:MIT Whirlwind 859: 857: 853: 848: 844: 841: 837: 833: 829: 823: 814: 810: 808: 804: 800: 796: 792: 788: 784: 781: 777: 774: 769: 766: 762: 758: 754: 750: 746: 742: 737: 733: 731: 727: 723: 719: 715: 708:Justification 705: 702: 694: 690: 687: 683: 679: 675: 671: 668: 665: 662: 658: 655: 651: 649: 645: 641: 640: 639: 637: 630:Microprograms 627: 625: 621: 620: 619:control store 614: 610: 606: 602: 592: 590: 586: 582: 577: 575: 571: 567: 562: 560: 555: 550: 546: 544: 533: 531: 526: 522: 517: 511: 507: 501: 498: 494: 490: 485: 483: 482:register file 479: 464: 462: 458: 457: 452: 448: 444: 439: 437: 433: 429: 425: 420: 418: 414: 410: 406: 405:state machine 401: 399: 395: 391: 387: 383: 379: 375: 371: 367: 363: 351: 346: 344: 339: 337: 332: 331: 329: 328: 323: 320: 318: 314: 311: 308: 305: 304: 303: 302: 298: 297: 291: 288: 286: 282: 279: 276: 272: 269: 267: 264: 261: 258: 255: 251: 248: 246: 242: 239: 237: 233: 230: 227: 224: 221: 218: 217: 216: 215: 211: 210: 205: 204:Recompilation 202: 200: 197: 195: 192: 188: 185: 183: 180: 179: 177: 174: 171: 170:Ahead-of-time 168: 167: 166: 165: 161: 160: 155: 152: 150: 147: 145: 142: 140: 137: 135: 132: 131: 130: 129: 126:Types of code 125: 124: 117: 114: 112: 109: 107: 104: 100: 97: 96: 95: 92: 91: 90: 87: 84: 81: 77: 74: 70: 67: 66: 65: 62: 61: 60: 57: 55: 52: 51: 50: 49: 45: 44: 41: 38: 37: 33: 19: 6534:Chip carrier 6472:Clock gating 6391:Mixed-signal 6292: 6288:Write buffer 6265:Control unit 6077:Clock signal 5816:accelerators 5798:Cypress PSoC 5455:Simultaneous 5272:Out-of-order 4904:Neuromorphic 4785:Architecture 4743:Belt machine 4736:Zeno machine 4669:Hierarchical 4581: 4528: 4519: 4504:by removing 4491: 4447: 4441: 4416: 4402:. Retrieved 4374: 4368: 4345:. Retrieved 4325: 4321: 4302:. Retrieved 4286:. Retrieved 4266: 4260: 4224: 4219: 4207:. Retrieved 4202: 4190: 4182:the original 4177: 4168: 4157:. Retrieved 4143: 4132:. Retrieved 4118: 4110:the original 4100: 4089:. Retrieved 4085:the original 4075: 4063: 4046: 4039: 4028:. Retrieved 4020:Heise Verlag 4013: 4003: 3994: 3989: 3977:. Retrieved 3968: 3962: 3951:. Retrieved 3935: 3929: 3921: 3915:. Retrieved 3905: 3893:. Retrieved 3862: 3846: 3833: 3821:. Retrieved 3801: 3794: 3782:. Retrieved 3773:. May 1996. 3758: 3747:. Retrieved 3743:the original 3738: 3728: 3708: 3701: 3690:. Retrieved 3686:the original 3681: 3671: 3652: 3646: 3634:. Retrieved 3630:the original 3620: 3609:. Retrieved 3593: 3587: 3576:. Retrieved 3560: 3554: 3543:. Retrieved 3527: 3521: 3510:. Retrieved 3494: 3488: 3476:. Retrieved 3461: 3451: 3439:. Retrieved 3430: 3421: 3409:. Retrieved 3395: 3375: 3368: 3343: 3337: 3327: 3301:New York, NY 3294: 3289:Allen Newell 3270: 3259:. 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Retrieved 2482: 2451: 2340: 2316: 2280: 2272: 2228: 2200: 2185: 2178: 2165: 2157: 2127: 2118: 2103:Please help 2091: 2065:V-70 series 2048: 2027:Intel Core 2 2012: 2008: 2005: 1993: 1987: 1983: 1979: 1975: 1973: 1952: 1931: 1926: 1922: 1918: 1914: 1912: 1896: 1892: 1890: 1887: 1881: 1878:field select 1877: 1875: 1870:Field value 1867:Field select 1860: 1837: 1833: 1824: 1711: 1703:Type of jump 1681: 1678: 1664: 1660: 1658: 1637: 1601: 1547: 1384: 1370: 1364: 1358: 1322: 1253: 1195: 1191: 1102: 1098:out-of-order 1081: 1077: 1065: 1062: 1043:all-digital 1041: 1021: 1001: 977: 955: 952: 943: 922: 906: 897: 891: 883:diode matrix 876: 870: 858:and wiring. 849: 845: 824: 820: 811: 770: 753:Data General 738: 734: 729: 711: 698: 685: 681: 677: 673: 653: 646:side of the 643: 635: 633: 616: 613:flash memory 598: 578: 566:control unit 563: 558: 554:machine code 551: 547: 543:player piano 539: 530:control unit 518: 502: 486: 475: 454: 450: 440: 421: 417:microprogram 416: 412: 402: 378:machine code 365: 359: 176:Just-in-time 153: 149:Machine code 69:Compile time 6319:Multiplexer 6283:Data buffer 5994:Single-core 5966:bit slicing 5824:Coprocessor 5679:Coprocessor 5560:performance 5482:Cooperative 5472:Speculative 5432:Distributed 5391:Superscalar 5376:Instruction 5344:Parallelism 5317:Speculative 5149:System/3x0 5021:Instruction 4798:Von Neumann 4711:Post–Turing 4304:October 27, 4209:15 February 3979:October 29, 3895:18 December 3784:November 7, 3682:mat.uson.mx 3478:October 18, 3222:October 29, 3002:(1): 4–11. 2820:October 29, 2789:January 22, 2652:www.iso.org 2569:January 22, 2436:Superscalar 2327:Pentium Pro 2121:August 2023 2015:Pentium Pro 1882:field value 1521:video cards 1342:Nintendo 64 1158:EMIDEC 1100 1094:Pentium Pro 1089:Intel 80486 1038:RISC enters 926:core memory 902:conditional 832:core memory 506:main memory 409:electronics 290:Zend Engine 271:Objective-C 139:Object code 134:Source code 111:Interpreter 59:Translation 6549:Categories 6439:management 6334:Multiplier 6195:Logic gate 6185:Sequential 6092:Functional 6072:Clock rate 6045:Data cache 6018:Components 5999:Multi-core 5987:Core count 5477:Preemptive 5381:Pipelining 5364:Bit-serial 5307:Wide-issue 5252:Structural 5174:Tilera ISA 5140:MicroBlaze 5110:ETRAX CRIS 5005:Comparison 4850:Load–store 4830:Endianness 4404:August 23, 4159:2008-02-25 4134:2020-01-16 4091:2018-03-21 4030:2017-08-28 3953:2012-08-27 3917:2023-10-27 3749:2013-11-07 3692:2015-08-08 3611:2020-01-14 3578:2020-01-14 3545:2020-01-14 3512:2020-01-14 3307:. p. 3261:2019-11-09 2764:2011-07-10 2737:2011-07-10 2657:2024-06-23 2540:2024-08-21 2463:References 2389:CPU design 2259:Cyrix 6x86 2196:pipelining 2029:and Intel 1961:System/370 1844:System/390 1661:horizontal 1629:AMD Am2900 1537:GDDR SDRAM 1500:(patch by 1482:, and the 1375:; 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