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Topic: Reduced Instruction Set Computer


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X86

  
  Reduced instruction set computer - Wikipedia, the free encyclopedia
The reduced instruction set computer, or RISC, is a microprocessor CPU design philosophy that favors a smaller and simpler set of instructions that all take about the same amount of time to execute.
Unfortunately, the term "reduced instruction set computer" is often mis-understood as claiming that there are fewer instructions in the instruction set of those machines.
Many in the computer industry criticized that the performance benefits were unlikely to translate into real-world settings due to the decreased memory efficiency of multiple instructions, and that that was the reason no one was using them.
en.wikipedia.org /wiki/RISC   (4185 words)

  
 Complex instruction set computer - Wikipedia, the free encyclopedia
A complex instruction set computer (CISC) is a microprocessor instruction set architecture (ISA) in which each instruction can execute several low-level operations, such as a load from memory, an arithmetic operation, and a memory store, all in a single instruction.
The term was coined in contrast to reduced instruction set computer (RISC).
Modern "CISC" CPUs, such as recent x86 designs like the Pentium 4, whilst they usually support every instruction that their predecessors did, are designed to work most efficiently with a subset of instructions more resembling a typical "RISC" instruction set.
en.wikipedia.org /wiki/CISC   (417 words)

  
 MSN Encarta - Search Results - Reduced Instruction Set Computer
Instruction Set, in computer science, the set of machine instructions that a microprocessor recognizes and can execute.
Complex Instruction Set Computer (CISC), in computer science, a processor that uses complex instructions at the assembly language level.
You reduce a fraction to lowest terms by finding an equivalent fraction in which the numerator and denominator are as small as possible.
encarta.msn.com /Reduced_Instruction_Set_Computer.html   (180 words)

  
 What’s the Difference Between RISC and CISC
Variable-length instructions were used to limit the amount of wasted space, although they do require special decoding circuits that count bytes within words and frame the instructions according to their byte length [MANO].
Another computer family that is classified as a complex instruction set computer is the Motorola 68000 family.
Reduced instruction set machines, unlike complex instruction set machine, use same length instructions so that the instructions are aligned on word boundaries and may be fetched in a single operation [APPL].
www.cstp.umkc.edu /~mullinsj/cs282/DifferenceBetweenRISCandCISC.htm   (1530 words)

  
 ReRISC Reconfigurable Reduced Instruction Set Computer
The mapping of instruction definitions into the computational array is independant of many array parameters, such as the size of the array.
A ratio of 2:1 in the computational array would imply that every 2 bits would have to perform an identical computation, but for most applications, that is not a great loss, since the granularity is often as coarse as 8:1.
By setting the ratio to 2:1 we can reduce the memory area by 50%, and hence reduce the overall area of the computational array by close to that amount.
www.xenatera.com /bunnie/proj/rerisc/rerisc.html   (1110 words)

  
 RISC - a Whatis.com definition   (Site not responding. Last check: 2007-10-20)
RISC (reduced instruction set computer) is a microprocessor that is designed to perform a smaller number of types of computer instructions so that it can operate at a higher speed (perform more millions of instructions per second, or MIPS).
Since each instruction type that a computer must perform requires additional transistors and circuitry, a larger list or set of computer instructions tends to make the microprocessor more complicated and slower in operation.
Among design considerations are how well an instruction can be mapped to the clock speed of the microprocessor (ideally, an instruction can be performed in one clock cycle); how "simple" an architecture is required; and how much work can be done by the microchip itself without resorting to software help.
whatis.techtarget.com /gDefinition/0,294236,sid3_gci214266,00.html   (404 words)

  
 The Franklin Institute Certficates of Merit - John Cocke   (Site not responding. Last check: 2007-10-20)
The candidate is Dr. John Cocke, a pioneer in the development of the Reduced Instruction Set Computer (the RISC machine).
Cocke's RISC concept was contrary to the established direction of increasingly complex instruction sets and machines, and was consequently at variance with the dominant ideas of that time.
RISC processors and RISC microprocessors are key components of many of the emerging parallel machine designs that are the vanguard of the next generation of computing.
www.fi.edu /tfi/exhibits/cocke.html   (615 words)

  
 Instruction Set Architecture (ISA)
The Instruction Set Architecture (ISA) is the part of the processor that is visible to the programmer or compiler writer.
Instructions were of varying length from 1 byte to 6-8 bytes.
The answer is that to make all instructions the same length the number of bits that are used for the opcode is reduced.
shekel.jct.ac.il /~citron/ca/isa.html   (904 words)

  
 RISC (Reduced Instruction Set Computer) (Linktionary term)
The instruction sets perform various tasks, such as moving values into registers or executing instructions to add the values in registers.
RISC designs, as the name implies, have a reduced set of instructions that improve the efficiency of the processor, but require more complex external programming.
His 80/20 rule spawned the development of RISC architecture, which reduces the number of instructions to only those that are used most.
www.linktionary.com /r/risc.html   (276 words)

  
 [No title]
Each instruction is the same length, so that it may be fetched in a single operation.
Instructions which access main memory(instead of registers) since main memory can be slow.
Since the instruction set is so simple, it uses up much less chip space; extra functions, such as floating point arithmetic units, can also be placed on the same chip.
www.cs.sjsu.edu /~lee/cs147/spring05_pres/RISC_PRESENTATION_032205_YangchaHo.ppt   (565 words)

  
 [No title]
RISC- acronym for reduced instruction set computer, a type of microprocessor that recognizes a relatively limited number of instructions.
Until the mid-1980s, the tendency among computer manufacturers was to build increasingly complex CPUs that had ever-larger sets of instructions.
One advantage of reduced instruction set computers is that they can execute their instructions very fast because the instructions are so simple.
www.escotal.com /cpu.html   (1017 words)

  
 The Ultimate RISC
In general, RISC machines are characterized by fixed format instructions and extensive use of pipelined execution, while CISC machines have variable length instructions and extensive use of microprogramming.
This is a complex instruction with 3 address fields (reducable to two if an accumulator is used), and the conditional branch phase of each instruction cycle depends on the results of the subtract phase of that instruction, inhibiting pipelined execution.
Some early drum machines, such as the British DEUCE computer, circa 1955, encoded the data part of their instruction set as a series of move instructions, but these machines typically also included a next-address field in each instruction, making them quite different from pure move machines.
www.cs.uiowa.edu /~jones/arch/risc   (2609 words)

  
 CISC - a Whatis.com definition - see also: complex instruction set computer   (Site not responding. Last check: 2007-10-20)
The term "CISC" (complex instruction set computer or computing) refers to computers designed with a full set of computer instructions that were intended to provide needed capabilities in the most efficient way.
Later, it was discovered that, by reducing the full set to only the most frequently used instructions, the computer would get more work done in a shorter amount of time for most applications.
RISC takes each of the longer, more complex instructions from a CISC design and reduces it to multiple instructions that are shorter and faster to process.
whatis.techtarget.com /definition/0,,sid9_gci213854,00.html   (209 words)

  
 Reduced Instruction Set Computer Architectures for VLSI - The MIT Press   (Site not responding. Last check: 2007-10-20)
This work demonstrates that the recent trend in computer architecture toward the use of increasingly complex instruction sets leads to the inefficient use of those scarce resources.
Reduced Instruction Set Computer architectures offer an alternative by allowing for the effective use of on-chip transistors in functional units that provide fast access to frequently used operands and instructions.
Reduced Instruction Set Computer Architectures for VLSI is the winner of the 1984 Doctoral Dissertation Award.
mitpress.mit.edu /catalog/item?tid=5550&ttype=2   (211 words)

  
 CISC Vs. RISC   (Site not responding. Last check: 2007-10-20)
The term 'RISC' (short for Reduced Instruction Set Computer) was later coined by David Patterson, a teacher at the University of California in Berkeley.
The RISC concept was used to simplify the design of the IBM PC/XT, and was later used in the IBM RISC System/6000 and Sun Microsystems' SPARC microprocessors.
The definition of 'Reduced' and 'Complex' instructions has begun to blur, RISC chips have increased in their complexity (compare the PPC 601 to the G4 as an example) and CISC chips have become more efficient.
www.amigau.com /aig/riscisc.html   (1126 words)

  
 OISC - TheBestLinks.com - Complex Instruction Set Computer, Reduced Instruction Set Computer, Vfd, ...   (Site not responding. Last check: 2007-10-20)
The OISC is the One Instruction Set Computer, by humorous analogy with RISC (Reduced Instruction Set Computer) and CISC (Complex Instruction Set Computer).
The instruction set of the OISC is even smaller than that of a RISC: it contains exactly one instruction.
In any instruction, the branch can be suppressed by pointing it at the instruction that would have been executed next in any case.
www.thebestlinks.com /OISC.html   (458 words)

  
 [No title]   (Site not responding. Last check: 2007-10-20)
RISC processors are faster than CISC processors because RISC processors have a reduced instruction set to execute.
RISC processors are more efficient than CISC processors because the reduced instructions present fewer bottlenecks that can potentially complicate processing.
On the other hand, RISC (reduced instruction set computer) is a computer whose processor works with only a small set of instructions and as a result can process information faster and more effectively than a typical computer w/ CISC design.
www.psyc.memphis.edu /TRG/cur_script/HardwareTopic/Latest/H10_Nov98.txt   (1023 words)

  
 "F-RISC - A 1.0 GOPS FAST REDUCED INSTRUCTION SET COMPUTER FOR SUPER WORKSTATION AND TERAOPS PARALLEL PROCESSOR ...   (Site not responding. Last check: 2007-10-20)
The influences of this earlier Berkeley RISC II ARPA contract on the present architecture are fairly strong because of this early interaction.
Instructions with 3 register references (op1, op2, dest) with an optional signed 8 bit immediate constants and 2 register instructions with a signed 16 bit immediate constant are supported.
From this collaboration the first evolved HBT was developed reduced the area of the emitter stripe from 1.4 µm by 3 µm to 1.2 µm by 1.7 µm (2.04 square µm area or approximately half the area of the 50 GHz baseline HBT).
www.ecse.rpi.edu /research/mcdonald/frisc/finalreports/spring95/fin0187.html   (15471 words)

  
 Citations: Reduced instruction set computers - Patterson (ResearchIndex)
For example, one might use FX 32 to statically translate from the x86 instruction set to the Alpha instruction set and then run the resulting binary on a SEA.
Therefore, in our tables of complexity, we indicate not just the number of instructions, but also the number of memory references and whether or not a branch is involved.
For sequential computation, the stability of the von Neumann model has permitted the development, over the last three decades, of a variety of high level languages and compilers.
citeseer.ist.psu.edu /context/104412/0   (2240 words)

  
 RISC Architectures
This increase coincided with the introduction of Reduced Instruction Set Computers (RISC).
RISC was also heralded a more quantitative approach to computer architecture, whereby careful experiments preceded the hardware design and sensible performance metrics were used to judge success.
Joy is the recipient of the Grace Murray Hopper Award from the Association for Computing Machinery, and of the Lifetime Achievement Award from the USENIX Association.
www.cs.washington.edu /homes/lazowska/cra/risc.html   (1434 words)

  
 Complex Instruction Set Computer   (Site not responding. Last check: 2007-10-20)
In a CISC the data and instruction share the same memory space, were as in a RISC they are separate.
This is not the case for RISC multiple cycles are need for this type of operation due to the pipeline.
Technically no instruction is single cycle because it needs to be fetched from memory which takes one or more cycles depending on the memoryspeed.
home.cfl.rr.com /ravon/cisc.htm   (272 words)

  
 A perspective on the 801/Reduced Instruction Set Computer
From the earliest days of computers until the early 1970s, the trend in computer architecture was toward increasing complexity.
It was observed that most of the complex instructions were seldom used.
Thus, a computer could be designed with only simple instructions without drastically increasing the path length or number of instructions required to implement an application.
domino.research.ibm.com /tchjr/journalindex.nsf/d9f0a910ab8b637485256bc80066a393/6b6514acb9a5d75185256bfa00685bce?OpenDocument   (167 words)

  
 Reduced Instruction Set Computer Architectures for VLSI
In this dissertation, the nature of general-purpose computations is studied, showing the simplicity of the operations usually performed and the high frequency of operand accesses, many of which are made to the few local scalar variables of procedures.
The architecture of the RISC I and II processors is presented.
They feature simple instructions and a large multi-window register file, whose overlapping windows are used for holding the arguments and local scalar variables of the most recently activated procedures.
sunsite.berkeley.edu /TechRepPages/CSD-83-141   (481 words)

  
 RISC - Glossary - CNET.com   (Site not responding. Last check: 2007-10-20)
While the original complex instruction set computing (CISC) chips had accomplished amazing things, chip designers were asking themselves, "How can we do even more?" In 1974, John Cocke of IBM Research decided to try an approach that dramatically reduced the number of instructions a chip performed.
These reduced instruction set processors ended up being not only faster than CISC chips, but easier and less expensive to manufacture, as well.
Motorola's PowerPC chip, which is commonly used in Macs, is a RISC chip.
www.cnet.com /Resources/Info/Glossary/Terms/risc.html   (124 words)

  
 EDN: RISC boards target real-time applications. (reduced instruction set computer CPUs)@ HighBeam Research   (Site not responding. Last check: 2007-10-20)
Reduced instruction set computer (RISC) boards for real-time applications allow more powerful real-time systems to be developed than can be done with complex instruction set computer (CISC) boards, according to manufacturers of the devices.
A single-processor RISC board could serve in some real-time applications that might previously have required tightly coupled multiprocessors.
RISC boards for real-time applications require that high-level languages be used to develop software for RISC processors, and the processors themselves require fast access to large memory arrays.
www.highbeam.com /library/doc0.asp?DOCID=1G1:7218980&refid=holomed_1   (184 words)

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