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Topic: Arithmetic and Logical Unit


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  Arithmetic and Logical Unit: Definition and Links by Encyclopedian.com
An Arithmetic and Logical Unit (ALU) is one of the core components of all Central Processing Units.
For these calculations a separate component, such as a divider or Floating Point Unit (FPU), is often used, although it is also possible that a microcode program may use the ALU to emulate these operations.
The ALU takes as inputs the data to be operated on and a code from the control unit indicating which operation to perform, and for output provides the result of the computation.
www.encyclopedian.com /al/ALU.html   (222 words)

  
 Digital operation unit - Patent 5636154
The digital operation unit also including a first set of switches connected between the ALU the registers, a second set of switches connected between the registers and one of the dual ALU input ports, and a third set of switches connected in parallel with the second between the registers and the data bus.
That is to say, in order to execute a variety of complex arithmetic and logical operations, frequent data shifts to and from an external memory are necessary because of the single data register 20.
Operation of ALU 100 is selected by an external control signal (not shown) and ALU 100 executes the arithmetic or logic operation with respect to the data input at first and second ALU input ports 84 and 85.
www.freepatentsonline.com /5636154.html   (983 words)

  
 Information processor - Patent 6810474
ALU# (306a, 306b, 306c, 306d) stores the number for identifying the arithmetic and logical unit which is used by the instruction decoded by the instruction decoder 113.
When the instruction terminated by the ALU is not for speculative execution and the result doesn't coincide with the past prediction result, the logical gate 515 executes the instruction in the so-called normal manner and generates a signal 555 assuming that the completion of the instruction has been made possible.
Moreover, logical gates 712, 713, 714, 715, 716 generate an ALU selection signal 775 and an HEU selection signal 776 which indicate which arithmetic and logical unit is to be used, the ALU 109 or the HEU 117, and a speculation-status signal 777 for indicating that the instruction execution is performed speculatively.
www.freepatentsonline.com /6810474.html   (9218 words)

  
 Logical Operations
Arithmetic and logical operations are performed in the CPU by the Arithmetic/Logical Unit (ALU).
Logical instructions are bit-oriented manipulations of data based on the mathematical logic operations and, or, and not.
Logical operations are applied to boolean variables which have two values: true and false, or 1 and 0.
www.cs.uaf.edu /2000/fall/cs301/notes/node52.html   (373 words)

  
 Kids.Net.Au - Encyclopedia > Arithmetic and Logical Unit
An Arithmetic and Logical Unit (ALU) is one of the core components of all Central Processing Units.
For these calculations a separate component, such as a divider or Floating Point Unit (FPU), is often used, although it is also possible that a microcode program may use the ALU to emulate these operations.
The ALU takes as inputs the data to be operated on and a code from the control unit indicating which operation to perform, and for output provides the result of the computation.
www.kids.net.au /encyclopedia-wiki/ar/Arithmetic_and_Logical_Unit   (206 words)

  
 Full floating point vector processor with dynamically configurable multifunction pipelined ALU - Patent 4589067
Parallel processing divides the data to be processed among concurrently operating arithmetic and logical units thereby obtaining faster processing by a factor that depends upon the number of individual, concurrently operating, arithmetic and logical units utilized.
The pipeline control sequencer, controlled by both the address generator and the master processing unit, is operative to synchronously provide upon the occurence of each clock pulse the next output code which configures the pipelined arithmetic and logical unit for the particular phase of the function evaluation corresponding to that clock pulse.
The pipelined arithmetic and logical unit includes a pair of register files designated M and Z, a user selectable fixed or a floating point format multiplier, and a user selectable fixed or a floating point format arithmetic and logical unit.
www.freepatentsonline.com /4589067.html   (6626 words)

  
 Arithmetic Logic Unit
The arithmetic logic unit executes arithmetic and logical operations.
The arithmetic logic unit performs logic functions such as AND, OR and NOT.
The other general-purpose registers hold data on which operations are to be performed by the arithmetic logic unit.
www.geocities.com /cfleri/arithmetic.html   (144 words)

  
 Arithmetic-Logic Unit (Alu) | World of Computer Science
The arithmetic-logic unit (ALU) is an area of the processor responsible for the rigorous processing of mathematical and logical operations required by programs.
Logical statements might be a little less familiar, but simple questions posed by the program such as "IF A = B GOTO 2300" ask the ALU to decide if the values A and B are the same and return the answer in the form true or false to the processor.
Because the ALU does not have control over the direction of the program, the question of how it knows what to evaluate and what to leave for processing by other components of the CPU is often raised.
www.bookrags.com /research/arithmetic-logic-unit-alu-wcs   (594 words)

  
 Central Processing Unit - MSN Encarta
The main function of the CPU is to perform arithmetic and logical operations on data taken from memory or on information entered through some device, such as a keyboard, scanner, or joystick.
The ALU performs specific operations such as addition, multiplication, and conditional tests on the data in its registers, sending the resulting data back to RAM or storing it in another register for further use.
During this process, a unit called the program counter keeps track of each successive instruction to make sure that the program instructions are followed by the CPU in the correct order.
encarta.msn.com /encyclopedia_761556091/Central_Processing_Unit.html   (572 words)

  
 The integer unit
The Integer Unit deals with either bytes or words (a word is usually 2 or 4 bytes): in general it takes two eight bit numbers, and gives one eight bit answer, or two words and gives another word as an answer.
These bit dictate whether the input is taken from a register or from memory; what logical or arithmetic operation is performed; whether the data is a byte or a word; and where the output is written.
The Integer Unit also has some "status" outputs: for example, if the answer is zero, the Z bit is set to 1; and if there was a "carry" the carry bit is set to 1.
www.erg.abdn.ac.uk /users/gorry/eg2069/integer-unit.html   (597 words)

  
 [No title]
ALUArithmetic and Logical Unit A component of a typical machine architecture where the arithmetic and logical operations are performed.
Arithmetic and Logical Unit See ALU array A derived type, a collection of subelements of identical type, indexed by an integer.
Also, the ability of a computer to access ``logical'' addresses that are not physically present in main memory, by storing parts of the logical address space on disk and loading into memory as necessary.
www.mathcs.duq.edu /~juola/front.detex   (20066 words)

  
 Arithmetic and logical unit - Arithmetic and logical unit
The arithmetic logic unit/arithmetic-logic unit (ALU) of a computer's CPU is a part of the execution unit, a core component of all CPUs.
The ALU takes as input the data to be operated on (called operands) and a code from the control unit indicating which operation to perform.
In many designs the ALU also takes/generates as inputs/outputs a set of condition codes from/to a status register; typically these codes are used to indicate cases such as carry-in or carry-out, overflow, divide-by-zero, etc.
www.infotechloco.com /Inf-Computer-Topics-A---B/Arithmetic-and-logical-unit.html   (246 words)

  
 C:\BELLBO~1\COMPSR&E\HTMFILES\00000345.HTM
Arithmetic overflow and underflow in any of the processing elements is detected and produces a trap.
The high degree of overlap in the control unit precludes an immediate response to an interrupt during the instruction which generates an arithmetic fault in some processing element.
Table 1 indicates the arithmetic and logical operations available for the three operand precisions.
research.microsoft.com /~gbell/computer_structures__readings_and_examples/00000345.htm   (635 words)

  
 Electronic Computers Within The Ordnance Corps, BRLESC
The operational unit, after some delays due to technical difficulties, was delivered to BRL on 15 May 1961 under Ordnance Contract No. DA-04-495-ORD-1500 at a total cost of $680,000.
The arithmetic unit is constructed of standard vacuum tube logical packages, with tube driven, crystal diode logical gating.
Since instructions are in numerical form, arithmetic operations may be performed on them, that is they may be manipulated in the arithmetic unit.
ftp.arl.mil /~mike/comphist/61ordnance/chap5.html   (2004 words)

  
 Art of Assembly: Chapter Three-3
The arithmetic and logical unit (ALU) is where most of the action takes place inside the CPU.
To keep the number of logic gates to a reasonably small set (tens or hundreds of thousands), CPU designers must necessarily restrict the number and complexity of the commands the CPU recognizes.
The control unit fetches this instruction's code from memory and places it in the decoding register for execution.
webster.cs.ucr.edu /AoA/DOS/ch03/CH03-3.html   (4325 words)

  
 Central Processing Unit
The Control Unit -- controls the fetching of instructions from the main memory and the subsequent execution of these instructions.
Among other tasks carried out are the control of input and output devices and the passing of data to the Arithmetic/Logical Unit for computation.
It is worth noting here that the only operations that the CPU can carry out are simple arithmetic operations, comparisons between the result of a calculation and other values, and the selection of the next instruction for processing.
www.cee.hw.ac.uk /~pjbk/pathways/cpp1/node8.html   (219 words)

  
 An Experimental 50-Megacycle Arithmetic Unit
An experimental 50-megacycle arithmetic unit has been built which performs a repetitive multiplication program and checks the results for errors.
These circuits include a full binary adder, a phase-locked frequency divider which provides a 3.125-megacycle secondary timing source, a reshaping and retiming circuit using germanium diodes and capacitive storage, a high-speed shift register, a high-speed indicator register, and a binary word generator.
In a 50-megacycle system the interdependence of the space and time dimensions is marked, and although this introduces problems which are not ordinarily encountered in computing systems, it may be used advantageously to provide features such as the variable-phase clock system used in the arithmetic unit.
domino.research.ibm.com /tchjr/journalindex.nsf/0b9bc46ed06cbac1852565e6006fe1a0/e5d0f66178b0066f85256bfa00683d11?OpenDocument   (250 words)

  
 Unit Studies at Builder Books
Unlike many unit studies, this one needs only math, phonics for young readers, and maybe spelling for some students to be complete.
The Unit Studies were created to help children take an active role in understanding nutrition with lots of hands-on activities and questions to ponder.
This comprehensive, systematic unit is a semester high school credit (horticulture), and with the marketing plan & practice, becomes a 1 year course.
www.bbhomeschoolcatalog.com /unit_studies.html   (1505 words)

  
 CHAPTER THREE: SYSTEM ORGANIZATION (Part 3)
This addition requires eight logic functions to decode the A, B, and C bits from the patch panel, but the extra circuitry is well worth the cost because it reduces the number of sockets that must be repeated for each instruction.
This is the bitwise logical not operation that inverts all the bits in the destination register or memory operand.
Instruct the ALU to add, subtract, compare, logically and, or logically or the values (one clock cycle).
www.arl.wustl.edu /~lockwood/class/cs306/books/artofasm/Chapter_3/CH03-3.html   (4281 words)

  
 arothmetic logic unit
The ALU is made up of devices called gates that receive one or more inputs and, based upon what function they are designed to perform, output a result.
Support for this activity is provided by one or more special ALU registers called accumulators, which can receive initial values from memory, hold the cumulative results of arithmetic and logical operations and transmit final result values back to memory.
due to arithmetic overflow, and whether the result produced was positive or negative and zero or non-zero, respectively (the latter pair of flags is sufficient to record the result of any comparison operation.
members.tripod.com /Raguraman/alu.htm   (530 words)

  
 Programmable sequential logic   (Site not responding. Last check: )
Access to the ALU is through an input multiplexer inputs of which are connected to the output of the memory and the outputs of the data registers and of the address registers.
The arithmetic and logic unit, of known type, operates on two source operands, which may be register contents, logic inputs, or memory words, and transfers results to a destination, such as a register, group of outputs, or memory location.
The example chosen is that of the sequential logic built up from TTL circuits, equipped with a direct access, modular memory, and designed to carry out all the logic functions required for the interconnection of a controlling minicomputer with a passive switching network of an automatic exchange.
www.sacnewsmonthly.com /invent/process_preparation_1_5-dimethylbicyclo_3_2_1_octan-8-ol/programmable_sequential_logic.html   (2116 words)

  
 DPANS94
Characters shall be at least one address unit wide, contain at least eight bits, and have a size less than or equal to cell size.
Arithmetic zero is represented as the value of a single cell with all bits clear.
Data space is the only logical area of the dictionary for which standard words are provided to allocate and access regions of memory.
www.taygeta.com /forth/dpans3.htm   (4770 words)

  
 D68000 - Digital Core Design
ALUArithmetic Logic Unit performs the arithmetic and logic operations during execution of an instruction.
It contains accumulator and related logic such as arithmetic unit, logic unit, multiplier and divider.
It is responsible for all external bus cycle actions such as: read & write, repeated read & write, halt and resume of bus cycles, bus arbitration provided by 3- and 2- wire system, correct bus and address errors handling, wait states cycle insertion and M6800 synchronous cycle generation.
www.dcd.pl /acore.php?idcore=20   (394 words)

  
 CSC 155 - NOTES FOR LECTURE 1, AUGUST 29, 2000
Arithmetic and Logical Unit (ALU): Responsible for performing calculations such as addition, subtraction...
Tells the input unit when information should be read into the memory unit, tells the ALU when information from the memory unit should be utilized in calculations, and tells the output unit when to send information from the memory unit to certain output devices.
Programs or data not actively being used by the other units are normally placed on secondary storage unit (such as disks) until they are needed.
servercc.oakton.edu /~glance/Files/Notes1.html   (982 words)

  
 Atari Roots - Chapter 3
The arms of the V are the ALU's inputs, and the bottom of the V is the ALU's output.
When a calculation or a logical operation is to be carried out by the ALU, one piece of data and an operand (an addition or a subtraction) instruction are deposited into one of the ALU's inputs (one arm of the V).
When the ALU is called upon to add or subtract two numbers, one of the numbers is put on a data bus and then sent to one of the ALU's inputs, along with an operand.
www.atariarchives.org /roots/chapter_3.php   (3115 words)

  
 Elec 422 -- The jwC Microprocessor
There are 6 processing states, a reset state (that the controller goes to when the restart signal is asserted), and an error state (that the controller goes to when the contents of the IR are changed during an instruction-- ideally, this should never happen).
Once every unit is in place and wired up, it is necessary to flatten the entire layout and test the chip from pad to pad, as if the layout were the chip itself.
The longest Crystal path is from the SADD input (the signal from the control unit telling the ALU that we are doing an add/subtract or comparison operation) to the flagZ output (the flag that holds the result of a comparison).
www.owlnet.rice.edu /~elec422/1996/jwc/jwc.html   (2734 words)

  
 Know your Computer - Processing2   (Site not responding. Last check: )
Arithmetic/Logical Unit (ALU) - is the part of the CPU that performs arithmetic and logical operations.
The CPU performs arithmetic and logical operations on data obtained from the memory or from different input devices.
A unit called the program counter is employed during this process, to keep track of each successive instruction, to make sure that the program instructions are followed by the CPU in the correct order.
www.public.asu.edu /~fmarti3/fp/proc2.html   (543 words)

  
 Arithmetic and Logic Unit...   (Site not responding. Last check: )
The Arithmetic Logic Unit carries out as the name suggests Arithmetic and Logical operations on the data made available to it.
Basic Arithmetic functions which an ALU can carry out are an addition and subtraction.
THe logical operation which can it can carry out greater than, equal to, less than comparision between two numbers.
library.thinkquest.org /C0125787/ALU.htm   (83 words)

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