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单词 adder
释义

adder


add·er 1

A0080100 (ăd′ər)n. One that adds, especially a computational device that performs arithmetic addition.

ad·der 2

A0080100 (ăd′ər)n.1. Any of several venomous snakes, especially a viper of the subfamily Viperinae.2. Any of several nonvenomous snakes, such as the hognose snake, often believed to be harmful.
[Middle English, from an addre, alteration of a naddre, a snake, from Old English nǣdre, snake.]

adder

(ˈædə) n1. (Animals) Also called: viper a common viper, Vipera berus, that is widely distributed in Europe, including Britain, and Asia and is typically dark greyish in colour with a black zigzag pattern along the back2. (Animals) any of various similar venomous or nonvenomous snakes[Old English nǣdre snake; in Middle English a naddre was mistaken for an addre; related to Old Norse nathr, Gothic nadrs]

adder

(ˈædə) n (Computer Science) a person or thing that adds, esp a single element of an electronic computer, the function of which is to add a single digit of each of two inputs

ad•der1

(ˈæd ər)

n. 1. the common European viper, Vipera berus. 2. any of various snakes resembling the viper. [before 950; late Middle English; replacing Middle English nadder (a nadder becoming an adder by misdivision), Old English næddre]

add•er2

(ˈæd ər)
n. a person or thing that adds. [1570–80]

adder

- A snake, it was first "a nadder," which was misanalyzed to "an adder."See also related terms for snake.
Thesaurus
Noun1.adder - a person who adds numbersadder - a person who adds numbers calculator, estimator, figurer, reckoner, computer - an expert at calculation (or at operating calculating machines)
2.adder - a machine that adds numbersadder - a machine that adds numbers calculating machine, calculator - a small machine that is used for mathematical calculations
3.adder - small terrestrial viper common in northern Eurasiaadder - small terrestrial viper common in northern Eurasiacommon viper, Vipera berusviper - venomous Old World snakes characterized by hollow venom-conducting fangs in the upper jawgenus Vipera, Vipera - type genus of the Viperidae
Translations
Natterοχιάadditionneurcouleuvrevipera

adder


deaf as an adder

Unable to hear anything. The deafness of an adder is referred to in the Bible. A: "I'm shouting, and he's ignoring me!" B: "Oh, he's deaf as an adder! Write down whatever you're trying to communicate to him." What are you, deaf as an adder? You hear me calling you for dinner, so get in here!See also: adder, deaf

*deaf as a post

deaf. (*Also:as ~.) When my cousin was a teenager, she played her drum set without ear protection, and she was as deaf as a post by the age of twenty-five. Mark can't hear you even if you shout; he's deaf as a post.See also: deaf, post

deaf as a post

Also, deaf as an adder. Unable to hear or to listen, as in Speak louder, Grandpa's deaf as a post. The first simile has its origin in John Palsgrave's Acolastus (1540): "How deaf an ear I intended to give him ... he were as good to tell his tale to a post." It has largely replaced deaf as an adder, alluding to an ancient belief that adders cannot hear; it is recorded in the Bible (Psalms 58:3-5). See also: deaf, post

deaf as a post

OLD-FASHIONEDIf someone is as deaf as a post, they are very deaf. My Dad is as deaf as a post.See also: deaf, post

deaf as an adder (or a post)

completely or extremely deaf. The traditional deafness of an adder is based on an image in Psalm 58:4: ‘the deaf adder that stoppeth her ear’.See also: adder, deaf

(as) deaf as a ˈpost

(informal) unable to hear anything: You’ll have to shout if you want her to hear you. She’s as deaf as a post.See also: deaf, post

deaf as a post

Unable to hear or to listen. The simile dates from the sixteenth century, when J. Palsgrave wrote (Acolastus, 1540), “He wotteth ful lyttel how deffe an eare I intended to gyue him . . . he were as good to tell his tale to a poste.” It caught on and has survived to the present, outliving such similes as deaf as an adder (first recorded in the Book of Psalms, 58:4–5), deaf as a beetle, and deaf as a white cat. See also fall on deaf ears; turn a blind eye/deaf ear.See also: deaf, post

adder


adder:

see viperviper,
any of a large number of heavy-bodied, poisonous snakes of the family Viperidae, characterized by erectile, hypodermic fangs. The fangs are folded back against the roof of the mouth except when the snake strikes. Vipers are distributed throughout Eurasia and Africa.
..... Click the link for more information. .

Adder

 

an analogue computing device whose output represents a quantity that is proportional to the sum of the input quantities, or signals. Mechanical adders are used primarily for the summing of displacements. The slide rule, for example, can be classed as a mechanical adder; it sums linear displacements. The differential gear is a mechanical adder that sums angular displacements. In electromechanical adders, the input and output quantities are mechanical displacements, and summation is carried out through use of the principles of electric circuits, particularly Kirchhoff’s laws. Electrical adders sum currents or voltages. The most common types of adders used in electronic analogue computers sum currents. To increase accuracy and raise the power and amplitude of the output signal, such adders are supplemented by operational amplifiers (seeCOMPUTING AMPLIFIER).

Adder

 

the basic component of the arithmetic unit of a digital computer. Adders are used to peform the operation of addition of numbers.

When decimal numbers are added digit by digit, the digits in the units digit place in the addends are added first. If the result is a one-digit number, it is entered in the units place of the final sum. If the result is a two-digit number, only the digit in the units place of this number is entered in the units place of the sum; the tens are carried—that is, the digit in the tens place is added to the digits in the tens places of the original addends. The addition operation is then carried out on the tens digits. The process is repeated for the higher order digits until the final sum is obtained. As an example, let us consider the addition of 157, 68, and 9. The digits 7, 8, and 9 are added first. Since the result is the two-digit number 24, the 4 is entered in the units place of the final sum, and the 2 is carried. The sum of 2, 5, and 6 is 13. The 3 is entered in the tens place of the final sum, and the 1 is carried. Since the sum of 1 and 1 is 2, the digit in the hundreds place in the final sum is 2. The final sum is thus 234.

When binary numbers are added digit by digit, the same process is used. The digits in the given digit place in the addends are summed, and to this result there is added the carry, if any, from the next lower place. Following the rules of addition in the binary number system, we thus obtain the digit in the given place of the final sum and the carry to the next higher place.

Figure 1. Schematic of a half-adder: (x) and (y) addends, (S) sum, (c) carry to next higher digit place

A multidigit adder for digit-by-digit addition usually consists of suitably connected single-digit adding units. The simplest such unit for the addition of binary numbers is called a half-adder. A half-adder may be formed, for example, from four logic elements (Figure 1): two AND gates, an OR gate, and a NOT gate, or inverter. The circuit of a half-adder may vary in accordance with the system of logic elements used. The half-adder adds the two numbers x and y to produce the sum digit S and the carry digit c (see Table 1). To construct a multidigit adder, however, a three-digit adding unit is necessary, since three numbers must be added: the addends xi and yi and the carry ci–1 from the next lower place. The output of such a three-input adding unit is the sum Si and the carry ci+1 to the next higher place. The outputs of such an adder for the various possible inputs are shown in Table 2. An example of a three-input adder is schematically presented in Figure 2.

Table 1. Inputs and outputs of a half-adder
InputsOutputs
xySc
0000
1010
0110
1101

A number of different circuit designs and combinations of elements are used in adders. The various types of adders differ in the following ways: number system used (for example, binary adders, decimal adders, and binary coded decimal adders), number of inputs (two-input and three-input), manner of handling multidigit numbers (serial, parallel, and serial-parallel), manner

Table 2. Inputs and outputs of a three-input adder
InputsOutputs
xiYiCi – 1SiCi + 1
00000
00110
01010
01101
10010
10101
11001
11111

of organizing the summation process (combinational and accumulating), and manner of organizing the carry circuits (sequential carry, ripple-through carry, group carry, and simultaneous carry). The type of adder chosen for a particular purpose depends primarily on the system of elements used in the computer and on the speed and economy requirements. Speed is one of the most important parameters of an adder. For the sake of speed in arithmetic operations, third-generation computers use not single-digit adders but group adders, which rapidly calculate the sums and carries for a group of digit places.

Figure 2. Schematic of a three-input adder consisting of two half-adders and an OR gate: (HA) half-adder, (xi) and (yi) addends, (ci – 1) carry from next lower digit place, (Si) sum, (ci + 1) carry to next higher digit place

Besides the basic operation of addition, most adders are also used for multiplication, division, and various logical operations, such as logical addition and logical multiplication.

REFERENCES

Kartsev, M. A. Arifmetika tsifrovykh mashin. Moscow, 1969.
Kagan, B. M. and M. M. Kanevskii. Tsifrovye vychislitel’nye mashiny i sistemy. Moscow, 1973.
Presnukhin, L. N. and P. V. Nesterov. Tsifrovye vychislitel’nye mashiny. Moscow, 1974.

L. N. STOLIAROV

adder

[′ad·ər] (computer science) A computer device that can form the sum of two or more numbers or quantities. (electronics) A circuit in which two or more signals are combined to give an output-signal amplitude that is proportional to the sum of the input-signal amplitudes. Also known as adder circuit. (vertebrate zoology) Any of the venomous viperine snakes included in the family Viperidae.

adder

11. a common viper, Vipera berus, that is widely distributed in Europe, including Britain, and Asia and is typically dark greyish in colour with a black zigzag pattern along the back 2. any of various similar venomous or nonvenomous snakes

adder

2 a person or thing that adds, esp a single element of an electronic computer, the function of which is to add a single digit of each of two inputs

adder

An elementary electronic circuit that adds the bits of two numbers together.

adder


adder

 any of numerous venomous elapid and viperine snakes; the death adder is found in Australia and New Guinea and the puff adder is found in Africa and Arabia. See also snakebite.

ad·der

(ad'ĕr), Common name for many members of the family Viperidae (the vipers), applied to several genera, although true adders are of the genus Vipera. [M.E. naddre, fr. O.E. nāedre]

adder

(ăd′ər)n.1. Any of several venomous snakes, especially a viper of the subfamily Viperinae.2. Any of several nonvenomous snakes, such as the hognose snake, often believed to be harmful.

ADDER


AcronymDefinition
ADDER➣Automatic Digital Data Error Recorder
ADDER➣Algorithm, Description, Development, Evaluation and Refinement

adder


Related to adder: puff adder, Full adder
  • noun

Synonyms for adder

noun a person who adds numbers

Related Words

  • calculator
  • estimator
  • figurer
  • reckoner
  • computer

noun a machine that adds numbers

Related Words

  • calculating machine
  • calculator

noun small terrestrial viper common in northern Eurasia

Synonyms

  • common viper
  • Vipera berus

Related Words

  • viper
  • genus Vipera
  • Vipera
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更新时间：2024/11/13 19:27:56