Minimal instruction set computer (MISC) is a central processing unit (CPU) architecture, usually in the form of a microprocessor, with a very small number of basic operations and corresponding opcodes, together forming an instruction set. Such sets are commonly stack-based rather than register-based to reduce the size of operand specifiers.
Such a stack machine architecture is inherently simpler since all instructions operate on the top-most stack entries.
One result of the stack architecture is an overall smaller instruction set, allowing a smaller and faster instruction decode unit with overall faster operation of individual instructions.
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Separate from the stack definition of a MISC architecture, is the MISC architecture being defined by the number of instructions supported.
Also, the instruction pipelines of MISC as a rule tend to be very simple. Instruction pipelines, branch prediction, out-of-order execution, register renaming, and speculative execution broadly exclude a CPU from being classified as a MISC architecture.[ citation needed ]
While 1-bit CPUs are otherwise obsolete (and were not MISCs nor OISCs), the first carbon nanotube computer is a 1-bit one-instruction set computer, and has only 178 transistors, and thus likely the lowest-complexity (or next-lowest) CPU produced so far (by transistor count).
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Some of the first digital computers implemented with instruction sets were by modern definition minimal instruction set computers.
Among these various computers, only ILLIAC and ORDVAC had compatible instruction sets.
The disadvantage of a MISC is that instructions tend to have more sequential dependencies, reducing overall instruction-level parallelism .
MISC architectures have much in common with some features of some programming languages such as Forth's use of the stack, and the Java virtual machine. Both are weak in providing full instruction-level parallelism. However, one could employ macro-op fusion as a means of executing common instruction phrases as individual steps (e.g., ADD,FETCH to perform a single indexed memory read).
Probably the most commercially successful MISC was the original INMOS transputer architecture that had no floating-point unit. However, many 8-bit microcontrollers, for embedded computer applications, qualify as MISC.
Each STEREO spacecraft includes two P24 MISC CPUs and two CPU24 MISC CPUs. [8] [9] [10] [11]
A central processing unit (CPU), also called a central processor, main processor, or just processor, is the most important processor in a given computer. Its electronic circuitry executes instructions of a computer program, such as arithmetic, logic, controlling, and input/output (I/O) operations. This role contrasts with that of external components, such as main memory and I/O circuitry, and specialized coprocessors such as graphics processing units (GPUs).
The Electronic Delay Storage Automatic Calculator (EDSAC) was an early British computer. Inspired by John von Neumann's seminal First Draft of a Report on the EDVAC, the machine was constructed by Maurice Wilkes and his team at the University of Cambridge Mathematical Laboratory in England. EDSAC was the second electronic digital stored-program computer, after the Manchester Mark 1, to go into regular service.
The history of computing hardware spans the developments from early devices used for simple calculations to today's complex computers, encompassing advancements in both analog and digital technology.
The Intel 8080 ("eighty-eighty") is the second 8-bit microprocessor designed and manufactured by Intel. It first appeared in April 1974 and is an extended and enhanced variant of the earlier 8008 design, although without binary compatibility. The initial specified clock rate or frequency limit was 2 MHz, with common instructions using 4, 5, 7, 10, or 11 clock cycles. As a result, the processor is able to execute several hundred thousand instructions per second. Two faster variants, the 8080A-1 and 8080A-2, became available later with clock frequency limits of 3.125 MHz and 2.63 MHz respectively. The 8080 needs two support chips to function in most applications: the i8224 clock generator/driver and the i8228 bus controller. The 8080 is implemented in N-type metal–oxide–semiconductor logic (NMOS) using non-saturated enhancement mode transistors as loads thus demanding a +12 V and a −5 V voltage in addition to the main transistor–transistor logic (TTL) compatible +5 V.
A microprocessor is a computer processor for which the data processing logic and control is included on a single integrated circuit (IC), or a small number of ICs. The microprocessor contains the arithmetic, logic, and control circuitry required to perform the functions of a computer's central processing unit (CPU). The IC is capable of interpreting and executing program instructions and performing arithmetic operations. The microprocessor is a multipurpose, clock-driven, register-based, digital integrated circuit that accepts binary data as input, processes it according to instructions stored in its memory, and provides results as output. Microprocessors contain both combinational logic and sequential digital logic, and operate on numbers and symbols represented in the binary number system.
In computer science, an instruction set architecture (ISA) is an abstract model that generally defines how software controls the CPU in a computer or a family of computers. A device or program that executes instructions described by that ISA, such as a central processing unit (CPU), is called an implementation of that ISA.
The Intel 8008 is an early 8-bit microprocessor capable of addressing 16 KB of memory, introduced in April 1972. The 8008 architecture was designed by Computer Terminal Corporation (CTC) and was implemented and manufactured by Intel. While the 8008 was originally designed for use in CTC's Datapoint 2200 programmable terminal, an agreement between CTC and Intel permitted Intel to market the chip to other customers after Seiko expressed an interest in using it for a calculator.
EDVAC was one of the earliest electronic computers. It was built by Moore School of Electrical Engineering, Pennsylvania. Along with ORDVAC, it was a successor to the ENIAC. Unlike ENIAC, it was binary rather than decimal, and was designed to be a stored-program computer.
The Intel 4004 is a 4-bit central processing unit (CPU) released by Intel Corporation in 1971. Sold for US$60, it was the first commercially produced microprocessor, and the first in a long line of Intel CPUs.
A stored-program computer is a computer that stores program instructions in electronically, electromagnetically, or optically accessible memory. This contrasts with systems that stored the program instructions with plugboards or similar mechanisms.
The ORDVAC, is an early computer built by the University of Illinois for the Ballistic Research Laboratory at Aberdeen Proving Ground. It was a successor to the ENIAC. It was based on the IAS architecture developed by John von Neumann, which came to be known as the von Neumann architecture. The ORDVAC was the first computer to have a compiler. ORDVAC passed its acceptance tests on March 6, 1952, at Aberdeen Proving Ground in Maryland. Its purpose was to perform ballistic trajectory calculations for the US Military. In 1992, the Ballistic Research Laboratory became a part of the U.S. Army Research Laboratory.
The ILLIAC I, a pioneering computer in the ILLIAC series of computers built in 1952 by the University of Illinois, was the first computer built and owned entirely by a United States educational institution.
Sir Maurice Vincent Wilkes was an English computer scientist who designed and helped build the Electronic Delay Storage Automatic Calculator (EDSAC), one of the earliest stored program computers, and who invented microprogramming, a method for using stored-program logic to operate the control unit of a central processing unit's circuits. At the time of his death, Wilkes was an Emeritus Professor at the University of Cambridge.
The von Neumann architecture—also known as the von Neumann model or Princeton architecture—is a computer architecture based on the First Draft of a Report on the EDVAC, written by John von Neumann in 1945, describing designs discussed with John Mauchly, J. Presper Eckert at University of Pennsylvania's Moore School of Electrical Engineering. The document describes a design architecture for an electronic digital computer with these components:
The Manchester Baby, also called the Small-Scale Experimental Machine (SSEM), was the first electronic stored-program computer. It was built at the University of Manchester by Frederic C. Williams, Tom Kilburn, and Geoff Tootill, and ran its first program on 21 June 1948.
David John Wheeler was a computer scientist and professor of computer science at the University of Cambridge.
In computer engineering, an orthogonal instruction set is an instruction set architecture where all instruction types can use all addressing modes. It is "orthogonal" in the sense that the instruction type and the addressing mode may vary independently. An orthogonal instruction set does not impose a limitation that requires a certain instruction to use a specific register so there is little overlapping of instruction functionality.
ILLIAC was a series of supercomputers built at a variety of locations, some at the University of Illinois at Urbana–Champaign. In all, five computers were built in this series between 1951 and 1974. Some more modern projects also use the name.
The history of general-purpose CPUs is a continuation of the earlier history of computing hardware.
The TMS1000 is a family of microcontrollers introduced by Texas Instruments in 1974.