Ripple Carry Adders

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(完整版)第五章 CMOS组合逻辑电路设计II

第五章CMOS组合逻辑电路设计II －动态CMOS电路第一节动态逻辑门电路的基本结构、原理、特点第二节多米诺（Domino）CMOS电路第三节改进的Domino CMOS电路第四节时钟CMOS （C2MOS）第一节动态逻辑门电路的基本结构、原理、特点一、预充－求值动态CMOS的基本结构和工作原理二、动态CMOS的特点三、动态CMOS的问题四、动态CMOS的级联静态电路：靠管子稳定的导通、截止来保持输出状态除状态反转外，输出始终与VDD和GND保持通路。

动态电路：靠电容来保存信息一、预充－求值动态CMOS 的基本结构和工作原理In 1In 2PDN In 3M e M p Clk Clk Out C L 预充－求值动态CMOS 电路的基本结构工作过程：➢预充阶段：Clk ＝0，Out 被Mp 预充到VDD ，Me 截止，无论输入何值，均不存在直流通路。

此时的输出无效。

➢求值阶段：Clk ＝1，Mp 截止，Me 导通，Out和GND 之间形成一条有条件的路径。

具体由PDN 决定。

若PDN 存在该路径，则Out 被放电，Out 为低电平，“0”。

如果不存在，则预充电位保存在CL 上，Out 为高电平“1”。

➢求值阶段，只能有与GND 间的通路，无与VDD 间的，一旦放电，不可能再充电，只能等下次。

预充FET 求值FET预充－求值动态CMOS 电路的工作原理预充预充求值输出只在此时有效),2,1(Xn X X F Y ⋅⋅⋅=当Clk ＝1时Clk OutClk ＝0时，输出为1，与输入无关OutClk Clk ABCM p M e on off 1off on((AB)+C)例PUNPUN 构成的动态CMOS 电路),2,1(Xn X X F Y ⋅⋅⋅=Clk ＝1时，输出为0，与输入无关当Clk ＝0时一般不用PUN 网络二、动态CMOS的特点•逻辑功能由下拉网络PDN实现。

其结构和设计与互补CMOS 和类NMOS的一样。

加法器

Lecture 12: AddersLecture 12: AddersLecture 12: AddersLecture 12: AddersLecture 12: Addersuse dual-rail domino throughout. Switching to static means that there must later be a con-version back to domino. Since clock skew must be budgeted at the conversion, this can degrade cycle time. Thus, as transistors become more plentiful, fully dual-rail adders become more popular.Good 64-bit logarithmic adders can operate in about 7 FO4 delays.6.0 Example: 64 bit Adder DesignTo illustrate some of the issues in a large-scale design, let us look at a complete 64 bit adder. The adder is built entirely from dual-rail domino. It employs two levels of carry selection to minimize delay. It is limited to only perform addition and does not accept a carry in; in contrast, most adders used in processors must optionally invert an input and add a carry to perform subtraction. Simulated in the HP14 0.6 micron process with esti-mated long wire loads, the adder has a latency of 6.4 FO4 delays.The adder architecture is illustrated in Figure 8. The adder is divided into 2, 4, 16, and 64 bit blocks. The gates in the critical path are labeled S or D for static or dynamic. The num-ber following the letter indicates the number of series transistors. This is a rough metric of the complexity and delay of the gate.In each of the 32 two-bit blocks, the 2-bit propagate and generate signals are computed from A and B. In each of 16 four-bit blocks, the 2-bit propagate and generate signals are combined into 4-bit propagates and generates. In the sixteen-bit blocks, the P4 and G4 sig-nals are further combined into P16 and G16 signals. Finally, in the top-level 64-bit block, the carries into each 16 bit block are computed. They are driven back to muxes in each 2-bit block to select the appropriate result.To do this, the adder must have calculated sums for each 16-bit block assuming the carry in was 0 and 1. This calculation itself is critical, so it is done with a smaller 16 bit logarith-mic adder that shares the 4 bit P/Gs with the 64 bit adder. In the middle fork of the picture, the 4 bit carries are computed from the 4-bit P and G signals. Then 2 bit carries are also produced. The 2-bit carries do an initial level of carry selection so that only 2-bit ripple carry adders, shown in the bottom form of the ﬁgure, are needed for speculative sum com-putation. The 16 bit and 2 bit carry selection is merged into a single large mux because both carry signals are critical. Notice how the inputs are buffered before the speculative sum generation to avoid loading the critical path.•p4 = p20p2116-bit LogicCarry in to 4 bit block b assuming cin to 16 bit block is c: cin4c b•cin400 = 0•cin410 = 1•cin401 = g40•cin411 = g40 + p40•cin402 = g41 + p41(g40)•cin412 = g41 + p41(g40 + p40)•cin403 = g42 + p42(g41 + p41(g40))•cin413 = g42 + p42(g41 + p41(g40 + p40))16-bit Propagates and Generates•g16 = g43 + p43(g42 + p42(g41 + p41g40))•p16 = p20p21p22p2364-bit LogicCarry in to 16 bit block b assuming cin to 16 bit block is c: cin16b•cin160 = 0•cin161 = g160•cin162 = g161 + p161(g160)•cin163 = g162 + p162(g161 + p161(g160))Complete schematics of the blocks are also shown in the following ﬁgures. The capacitors represent lumped capacitance of long wires. Large gates are necessary in the 16 and 64 bit blocks to drive the wires and the heavy loads attached.FIGURE 9. 2-bit block schematicThe 2-bit blocks contain the 2-bit P,G logic, the result selection multiplexors, and the buff-ered 2-bit sum computation logic.FIGURE 10. 4-bit block schematicThe 4-bit blocks contain 2 2-bit blocks, 4-bit P,G logic, and logic to compute the carries into each 2-bit block.FIGURE 11. 16-bit block schematicThe 16-bit block contains 4 4-bit blocks, the 16-bit P/G logic, and gates to compute carries in to each 4 bit block.FIGURE 12. 64-bit block schematicFinally, the 64-bit block, representing the entire adder, contains 4 16-bit blocks and logic to compute the carry in to each 16 bit block.7.0 Ling AddersA clever designer noticed another way to write the adder equations which slightly reduces the critical path in the carry chain. Adders are such a specialized circuit that such savings is signiﬁcant; the technique is now known as the “Ling” adder.The Ling adder is based on an observation about the 4-bit generate and propagate signals. The conventional signals are deﬁned below, repeated from earlier equations:P4 = P3P2P1P0(EQ 7) G4 = G3 + G2P3 + G1P2P3 + G0P1P2P3 = G3 + P3(G2 + P2(G1 + P1G0))(EQ 8) The equations could be rewritten in terms of A and B inputs:P4 = (A3+B3)(A2+B2)(A1+B1)(A0+B0)(EQ 9)G4 = A3B3 + (A3 + B3)(A2B2 + (A2 + B2)(A1B1 + (A1 + B1)A0B0))(EQ 10) This G4 equation is too complicated to efﬁciently implement in a single domino gate because it would require too many series transistors. However, if we introduce a “Pseudo-generate” signal H4 such that G4 = H4*P3, we ﬁnd that H4 is easier to implement:H4 = G3 + G2 + G1P2 + G0P1P2 = A3B3 + (A2B2 + (A2 + B2)(A1B1 + (A1 + B1)A0B0))(EQ 11) Indeed, H4 can be built from a domino gate with 4 series transistors.As long as the AND of H4 and P3 occurs before G4 is actually used, the rest of the carry chain can be built using H4 in place of G4. Therefore, the four bit propagates and pseudo-generates can be computed in a single complex stage of domino logic, rather than in two gates as given in the previous section. It turns out that the gating with P3 can be cleverly woven into a non-critical path so the Ling adder may be slightly faster than a regular loga-rithmic adder.Naffziger describes an excellent implementation of a 64-bit Ling adder used on HP PA-RISC chips in ISSCC96. The paper is unfortunately terse, but a Verilog model with the complete logic equations may help explain the adder operation (see the Ling Adder hand-out). The adder runs in 7 FO4 delays and is remarkably compact.The adder implementation uses another trick of “pseudo-complements” to simplify design. Normally, dual-rail _h and _l signals are true complements of each other. This means that different gates must be designed for the _h and _l paths using DeMorgan’s law. Remarkably, most logic in an adder can be designed by using the same gates for _h and _l. Although the _h and _l signals are no longer true complements of each other, when they get consumed at the end of carry generation, the correct carries can be computed. The mathematics justifying this is nicely explained by Wang et. al in JSSC Feb. 1997. As a result, only half as many types of gates must be designed and laid out.8.0 Multiple Input AddersSometimes it is necessary to add more than 2 N-bit numbers. This can be done by using CSAs to add the numbers and produce a sum and a carry output. Then a regular adder, using any of the architectures above, can add the sums and carries. The regular adder is often called a carry-propagate adder (CPA) to distinguish it from a CSA.For example, consider adding three 4-bit numbers X, Y, and Z. The addition can be done with a 3:2 CSA and a CPA:。

改进的共享布尔逻辑进位选择加法器设计

改进的共享布尔逻辑进位选择加法器设计作者：***来源：《现代信息科技》2024年第04期收稿日期：2023-10-12DOI：10.19850/ki.2096-4706.2024.04.013摘要：在當今高度数字化和计算密集型的环境下，设计出高速和低功耗的加法器，例如进位选择加法器（Carry Select Adder， CSLA）是至关重要的。

基于此提出一种改进共享布尔逻辑进位选择加法器。

与现有设计相比，该设计在牺牲部分功耗和速度的基础上，减少了晶体管数量。

该设计采用TSMC65 nm工艺在Cadence中实现了4位的设计。

仿真结果显示，相对于Fast Adder Module-2（FAM2）进位选择加法器，该方案的晶体管数量、功耗和功耗延时积分别降低了8.91%、8.13%和6.02%。

关键词：进位选择加法器；晶体管数量；功耗；延迟中图分类号：TP332.2；TP391.9 文献标识码：A 文章编号：2096-4706（2024）04-0061-05Design of an Improved Shared Boolean Logic Carry Select AdderWU Shenglin（School of Computer Science and Engineering， Anhui University of Science and Technology， Huainan 232001， China）Abstract： In today's highly digitized and computationally intensive environment， it is crucial to design high-speed and low-power adders， such as Carry Select Adders （CSLA）. Based on this， an improved shared Boolean logic Carry Select Adder is proposed. Compared to existing designs， this design reduces the number of transistors on the basis of sacrificing some power consumption and speed. This design utilizes TSMC65 nm technology to achieve 4-bit design in Cadence. The simulation results show that compared to the Fast Adder Module-2 （FAM2） Carry Select Adder， this scheme reduces the number of transistors， power consumption， and power consumption delay product by 8.91%， 8.13%， and 6.02%， respectively.Keywords： Carry Select Adder; the number of transistors; power consumption; delay0 引言随着超大规模集成电路（Very Large Scale Integration， VLSI）系统在消费电子产品和便携式设备中的持续进步，迫切需要解决的挑战之一是实现高速计算、低功耗和小面积开销。

英语单词精解系列[高中人教必修3单元2]第七十三篇

英语单词精解系列[高中人教必修3单元2]第七十三篇fibre释义_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ n. 纤维；纤维制品短语_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ natural fibre:天然纤维;自然纤维;植物纤维;然纤维chemical fibre:化学纤维;化学合成纤维;化纤;纺织品英语acetate fibre:醋酯纤维;乙酸纤维;artificial fibre:醋酸纤维;醋酸织维glass fibre:人造纤维;人工制造纤维;人造;纺织品英语Dietary fibre:玻璃纤维;玻璃丝;玻璃;法国沙特尔大教堂的宗教玻璃画Polyamide Fibre:膳食纤维;食用纤维;饮食纤维素;食物纤维modal fibre:聚酰氨纤维;聚酰胺纤维;锦纶;聚酰胺dark fibre:莫代尔纤维;modal纤维例句_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _1.N-COUNT A fibre is a thin thread of a natural or artificial substance, especially one that is used to make cloth or rope. 纤维2.N-COUNT A fibre is a thin piece of flesh like a thread which connects nerve cells in your body or which muscles are made of. 纤维组织3.N-VAR A particular fibre is a type of cloth or other material that is made from or consists of threads. 纤维制品4.N-UNCOUNT Fibre consists of the parts of plants or seeds that your body cannot digest. Fibre is useful because it makes food pass quickly through your body. (植物) 纤维lose weight释义_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ v. 减肥；体重减轻短语_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Lose More Weight:减更多的肥lose of weight:重量损失lose some weight:减肥;降体重;失去一些重量;减减肥lose one weight:瘦了lose my weight:减肥lose off weight:失去了重量;失去起飞重量lose e weight:减肥;体重减轻lose sonic weight:减肥to lose unwanted weight:摆脱负担in debt释义_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 负债；欠情短语_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Call in a debt:要求还清一笔债款being in moderate debt:适度负债In-debt Financing:负债融资crisisi in sovereign debt:主权债券危机be in great debt:拉一屁股债reduction in longterm debt:长期负债减少in-debt management:负债经营Forever In Your Debt:歌曲名称be in mutual debt:互负债务curiosity音标_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 英[kjʊərɪ’ɒsɪtɪ] 美[,kjʊrɪ’ɑsəti]附加_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ [ 复数curiosities ]释义_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ n. 好奇，好奇心；珍品，古董，古玩短语_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ epistemic curiosity:详细翻译perceptual curiosity:感知型好奇idle curiosity:随意的好奇心;赫拉克勒斯;猎奇心;求知的本能sex curiosity:性的好奇心impertinent curiosity:过分的好奇心Curiosity Tendency:好奇倾向Curiosity Stream:好奇心流媒体By curiosity:凭好奇心Cabinet Curiosity:珍宝柜例句_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 1.N-UNCOUNT Curiosity is a desire to know about something. 好奇心2.N-COUNT A curiosity is something that is unusual, interesting, and fairly rare. 奇珍异宝slim音标_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 英[slɪm] 美[slɪm]释义_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ adj. 苗条的；修长的；微小的；差的vt. 使…体重减轻；使…苗条vi. 减轻体重；变细n. (Slim)人名；(阿拉伯)萨利姆；(英、西)斯利姆短语_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Carlos Slim:卡洛斯·斯利姆;斯利姆;史林姆;姆·埃卢Slim Fit:男;修身款;修身剪裁;修身版Slim PC:三宝电脑;计算机Slim Bezel:极窄边框;窄边框设计Slim design:超薄的设计;超薄设计;超溥设计Slim Type:超薄型;之笔记本电脑用Finger Slim:纤薄如指Slim notebook:超薄型笔记型计算机例句_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 1.ADJ A slim person has an attractively thin and well-shaped body. 苗条的; 纤细的[表赞许]2.ADJ A slim book, wallet, or other object is thinner than usual. 薄的3.ADJ A slim chance or possibility is a very small one. (机会或可能性) 微小的4.V-T If an organization slims its products or workers, it reduces the number of them that it has. 缩减[商业]vitamin音标_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 英[’vɪtəmɪn; ’vaɪt-] 美[’vaɪtəmɪn]释义_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ n. [生化] 维生素；[生化] 维他命短语_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Vitamin C:维生素C;维他命C;抗坏血酸;维生素Vitamin poisoning:维生素过多症vitamin B2:维生素B;核黄素;核黄素标准品;维生素B2标准品Vitamin D3:维生素D;维他命D3抗佝偻病素Vitamin B5:维生素B;泛酸;泛酸钙liposoluble vitamin:脂溶性维生素vitamin water:维他命获得;维生素水;维他命vitamin requirement:维生素需要;维生素需要量;维生素须要量;需要量vitamin premix:维生素预混料;维生素混合物例句_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _1.N-COUNT Vitamins are substances that you need in order to remain healthy, which are found in food or can be eaten in the form of pills. 维生素cucumber音标_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 英[’kjuːkʌmbə] 美[’kjʊ,kʌmbɚ]释义_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ n. 黄瓜；胡瓜短语_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ pickled cucumber:酸黄瓜;黄瓜泡菜;腌黄瓜;酱黄瓜Cucumber Mosaic:黄瓜花叶病;花叶病;黄瓜花叶病毒;胡瓜嵌纹病greenhouse cucumber:温室黄瓜;日光温室黄瓜;大棚黄瓜Cetriolo Cucumber:黄瓜;青瓜Sliced cucumber:黄瓜片;切片的大黄瓜cucumber seedlings:黄瓜幼苗;黄瓜苗;低温;黄瓜cucumber timberrot:黄瓜菌核病mini cucumber:小黄瓜;迷你黄瓜例句_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _1.N-VAR A cucumber is a long thin vegetable with a hard green skin and wet transparent flesh. It is eaten raw in salads. 黄瓜flavour释义_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ n. 香味；滋味vt. 给……调味；给……增添风趣短语_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Emulsion flavour:乳化香精special flavour:风味flavour reversion:变味cardboard flavour:纸板味stale flavour:霉味acrid flavour:味辛cheesy flavour:干酪风味smoky flavour:烟熏味flavour score:香例句_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _1.N-VAR The flavour of a food or drink is its taste. 味道2.N-COUNT If something is orange flavour or beef flavour , it is made to taste of orange or beef. (某种) 味道3.V-T If you flavour food or drink, you add something to it to give it a particular taste. 给(食物或饮料) 调味fry音标_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 英[fraɪ] 美[fraɪ]附加_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ [ 复数fries 过去式fried 过去分词fried 现在分词frying ]释义_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ v. 油炸，油煎；（被阳光）灼伤；（非正式）用电刑处死n. 鱼苗；油炸食品；炒杂烩菜；油炸食品聚餐会；炸薯条n. (Fry) （美）弗赖伊（人名）短语_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Stephen Fry:史蒂芬·弗莱;斯蒂芬·弗雷;斯蒂芬·弗莱;英国演员斯蒂芬·弗雷Pat Fry:帕特·弗莱;帕特;法拉利fry vt:油煎;油炸Elizabeth Fry:伊丽莎白•弗赖伊;伊丽莎白弗赖伊;伊丽莎白·弗莱;伊丽莎白·弗赖伊Fry Oyster:蚝仔酥;蚵仔酥Michael Fry:迈克尔·弗莱;米歇尔·弗莱Shirley Fry:雪莉·弗莱;雪莉弗莱Margery Fry:马杰里·弗莱;弗莱女士fry y:油煎;煎鸡蛋;油炸;用油炸例句_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _1.V-T When you fry food, you cook it in a pan that contains hot fat or oil. 炸2.V to kill or be killed by electrocution, esp in the electric chair (用电椅)杀死; (被电椅)杀死[美国英语] [slang]3.N the act of preparing a mixed fried dish or the dish itself 炒杂烩菜[英国英语] [非正式]4.N-PLURAL Fries are the same as . 同French fries5.N-PLURAL the young of various species of fish 鱼苗benefit音标_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 英[’benɪfɪt] 美[’bɛnɪfɪt]释义_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ n. 利益，好处；救济金vt. 有益于，对…有益vi. 受益，得益短语_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Benefit dandelion:蒲公英粉;蒲公英蜜粉external benefit:外部收益;外部利益;收益外泄benefit clusters:利益群体;长处群体;益处群体benefit tax:受益税;保险赔款税;一种受益税;收益税benefit performance:义演;为正义或公益事业筹款而演出;缞benefit headlines:利益式标题;好处式标题;利益式benefit premium:福利津贴;详细翻译pension benefit:抚恤金福利;退休津贴;退休金福利;退休费financial benefit:结算期;财务效益例句_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _1.N-VAR The benefit of something is the help that you get from it or the advantage that results from it. 益处;成效2.N-UNCOUNT If something is to your benefit or is of benefit to you, it helps you or improves your life. 好处</p>3.V-T/V-I If you benefit from something or if it benefits you, it helps you or improves your life. 有益于;得益4.N-UNCOUNT If you have the benefit of some information, knowledge, or equipment, you are able to use it so that you can achieve something. 优势5.N-VAR Benefits are money or other advantages which come from your job, the government, or an insurance company. 福利6.N-COUNT A benefit , or a benefit concert or dinner, is an event that is held in order to raise money fora particular charity or person. 义演[oft N n]7.→ see also fringe benefit8.PHRASE If you give someone the benefit of the doubt , you treat them as if they are telling the truth or as if they have behaved properly, even though you are not sure that this is the case. 姑且信其为真9.PHRASE If you say that someone is doing something for the benefit of a particular person, you mean that they are doing it for that person. 为了某人的利益mutton音标_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 英[’mʌt(ə)n] 美[’mʌtn]释义_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ n. 羊肉短语_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ roast mutton:烧羊肉块;考羊肉;羊肉烤braised mutton:锅烧羊肉;香焖羊肉;罐焖羊肉;红烧羊肉mutton chop:羊排;络腮胡mutton fat:羊油;白色羊脂样;羊脂Mutton cutlet:羊角饼mutton cloth:较松平针织物;羊肉布canned mutton:羊肉罐头;罐装羊肉fried mutton:羊扒;烤羊肉jerked mutton:风干羊肉条例句_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 1.N-UNCOUNT Mutton is meat from an adult sheep that is eaten as food. 羊肉customer音标_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 英[’kʌstəmə] 美[’kʌstəmɚ]释义_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ n. 顾客；家伙短语_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Customer Message:客户留言;攻丝机视频;联系我们;顾客留言customer value:顾客价值;客户价值;顾客価値;客户确定价值Customer base:客户群;客户基础customer relationship:客户关系;顾客关系;服务;消费者关系potential customer:潜在顾客;潜在客户;潜在主顾;潜在的顾客customer statement:客户结单;客户对数单;客户月结报告customer support:客户支持;客户服务;基带开发工程师;客户支援Customer Feedback:客户反馈;顾客反馈;客户反馈中心Our Customer:我们的客户;我们的项目;咱们的客户例句_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 1.N-COUNT A customer is someone who buys goods or services, especially from a shop. 顾客diet音标_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 英[’daɪət] 美[’daɪət]附加_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ [ 过去式dieted 过去分词dieted 现在分词dieting ]释义_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ n. 饮食；食物；规定饮食vi. 节食vt. [医] 照规定饮食n. (Diet)人名；(法)迪耶短语_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Balanced diet:均衡膳食;平衡膳食;均衡的饮食;平衡饮食diet pills:减肥药;减肥药丸Diet Therapy:饮食治疗;食治;膳食疗法;饮食疗法light diet:易消化饮食;易消化的饮食;清淡饮食;轻淡Grapefruit Diet:柚子减肥法Diet Cola:健怡可乐;健怡饮料;日常饮食冒号Zone Diet:区域减肥法;区域节食法;减肥法;区域饮食法APE DIET:人猿瘦身法;类人猿瘦身法fever diet:热病饮食例句_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _1.N-VAR Your diet is the type and variety of food that you regularly eat. 日常饮食2.N-VAR If you are on a diet , you eat special kinds of food or you eat less food than usual because you are trying to lose weight. (因减肥而吃的) 规定饮食3.N-COUNT If a doctor puts someone on a diet , he or she makes them eat a special type or variety of foods in order to improve their health. (医生为病人规定的) 特种饮食4.N-COUNT If you are fed on a diet of something, especially something unpleasant or of poor quality, you receive or experience a very large amount of it. 大量(不愉快的事或质量差的东西)5.V-I If you are dieting , you eat special kinds of food or you eat less food than usual because you are trying to lose weight. 节食6.ADJ Diet drinks or foods have been specially produced so that they do not contain many calories. (饮食) 低热量的[ADJ n]7.N a legislative assembly in various countries, such as Japan 议会discount音标_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 英[’dɪskaʊnt] 美[dɪs’kaʊnt]释义_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ n. 折扣；贴现率vi. 贴现；打折扣出售商品vt. 打折扣；将…贴现；贬损；低估；忽视短语_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ quantity discount:数量折扣;大批量折扣;折扣量;高额保险折扣优惠special discount:特别折扣;特价区;特扣;出格扣头Discount Charges:贴现利息;贴现利钱;贴现费用;贴现extra discount:额外折扣;额外成本functional discount:功能折扣;功能性折扣;翻译discount interest:贴现利息;贴现息;贴息;翻译discount liability:折价债务volume discount:总购量折扣;数量折扣;Discount Houses:总额折扣;批发折扣例句_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _1.N-COUNT A discount is a reduction in the usual price of something. 折扣2.V-T If a shop or company discounts an amount or percentage from something that they are selling, they take the amount or percentage off the usual price. 对…打折3.V-T If you discount an idea, fact, or theory, you consider that it is not true, not important, or not relevant. 不理会protein音标_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 英[’prəʊtiːn] 美[’protin]释义_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ n. 蛋白质；朊adj. 蛋白质的短语_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ transmembrane protein:跨膜蛋白;motor protein:跨膜蛋白质;穿膜蛋白protein subunit:马达蛋白;摩托蛋白Total Protein:蛋白质亚基;蛋白亚基;蛋白质亚单位fibrous protein:总蛋白;血清总蛋白;蛋白质总量;总蛋白质protein purification:纤维状蛋白质;纤维蛋白;纤维状蛋白;纤维卵白docking protein:蛋白纯化;蛋白质净化;蛋白质纯化手册Ideal Protein:停靠蛋白;停泊蛋白;船坞蛋白;对接蛋白protein binding:无象源;理想蛋白质;理想蛋白;是与理想蛋白质例句_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _1.N-MASS Protein is a substance found in food and drink such as meat, eggs, and milk. You need protein in order to grow and be healthy. 蛋白质lie附加_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ [ 过去式lay 过去分词lain 现在分词lying ]释义_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ vi. 躺；说谎；位于；展现vt. 谎骗n. 谎言；位置n. (Lie)人名；(罗、挪、瑞典)利；(中)李(普通话·威妥玛)短语_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ white lie:善意的谎言;不怀恶意的谎言;无恶意的谎言;白色谎言Lie derivative:李导数;lie导数lie with:取决于;在于;应由;作出决定等fetal lie:胎产式lie fallow:休闲;休闲类;休闲舒适lie by:躺在边上;靠近;休息lie off:位于;稍离;与…保持一定距离Never lie:不要说谎;绝不要撒谎;永远不会说谎;从不说谎lie behind:为某事之理由;在…之后;是原因;是．．．的根据nut音标_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 英[nʌt] 美[nʌt]附加_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ [ 过去式nutted 过去分词nutted 现在分词nutting ]释义_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ n. 螺母，螺帽；坚果；难对付的人，难解的问题vi. 采坚果n. (Nut)人名；(阿拉伯)努特；(柬)努短语_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ hexagon nut:六角螺母;六角螺帽;螺帽;六角螺冒Nut brown:深棕色;咖啡色;果褐色hexagonal nut:六角螺母;六角螺丝帽;六角螺帽;六角螺女Castellated nut:槽式螺母;nut wrench:槽顶螺母;槽形螺母;蝶形螺母ring nut:螺母扳手;Retaining Nut:螺帽扳手;螺丝起子扳手;扳子securing nut:环型螺母;环形螺母;带环螺帽;环首螺帽clip nut:锁紧螺母;止动螺母;固定螺母;紧固螺母例句_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _1.N-COUNT The firm shelled fruit of some trees and bushes are called nuts . Some nuts can be eaten. 坚果2.→ see also peanut3.N-COUNT A nut is a thick metal ring which you screw onto a metal rod called a bolt. Nuts and bolts are used to hold things such as pieces of machinery together. 螺母4.N-COUNT If you describe someone as, for example, a baseball nut or a health nut , you mean that they are extremely enthusiastic about the thing mentioned. 狂热者[非正式]5.ADJ If you are nuts about something or someone, you like them very much. 狂热于…的[非正式] [v-link ADJ ’about’ n] </p>6.ADJ If you say that someone goes nuts or is nuts , you mean that they go crazy or are very foolish. 发疯的; 愚蠢的[非正式] [v-link ADJ] </p>7.PHRASE If someone goes nuts , they become extremely angry. 大发雷霆[非正式]pepper音标_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 英[’pepə] 美[’pɛpɚ]释义_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ n. 胡椒；辣椒；胡椒粉vt. 加胡椒粉于；使布满n. (Pepper)人名；(英、德、意)佩珀短语_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ bell pepper:菜椒;甜椒;灯笼椒;柿子椒Red pepper:红椒;红辣椒;辣椒;红胡椒serrano pepper:塞拉诺辣椒Long Pepper:筚茇;荜拔;荜茇粉末;荜茇pepper shaker:胡椒粉瓶;胡椒瓶;胡椒摇瓶;胡椒粉摇罐pepper pot:胡椒瓶;辣味浓汤;胡椒粉盒;胡椒粉瓶步pepper oil:胡椒油;花椒油;辣椒油;黑胡椒油〔增香剂Jamaica pepper:牙买加胡椒粉;众香子;牙买加胡椒Pepper mint:薄荷色;薄荷茶;胡椒薄荷;薄荷例句_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _1.N-UNCOUNT Pepper or black pepper is a hot-tasting spice used to flavour food. 胡椒2.N-COUNT A pepper , or a bell pepper , is a hollow green, red, or yellow vegetable with seeds inside it. 椒类3.V-T If something is peppered with small objects, a lot of those objects hit it. (以小物体) 大量击中[usu passive]sigh音标_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 英[saɪ] 美[saɪ]释义_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ vi. 叹息，叹气n. 叹息，叹气vt. 叹息，叹气短语_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _A Sigh:正在翻译Silent Sigh:寂静的叹息The Sigh:叹气的内涵;叹气的内在TEN SIGH:叹十声SIGH BRIDGE:叹息桥Happy sigh:逍遥叹Cry sigh:哀声叹气sigh checks:在支票上签名例句_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _1.V-I When you sigh , you let out a deep breath, as a way of expressing feelings such as disappointment, tiredness, or pleasure. 叹气2.N-COUNT Sigh is also a noun. 叹气3.PHRASE If people breathe or heave a sigh of relief , they feel happy that something unpleasant has not happened or is no longer happening. 松了口气consult音标_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 英[kən’sʌlt] 美[kən’səlt]释义_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ vt. 查阅；商量；向…请教vi. 请教；商议；当顾问短语_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Please Consult:欢迎咨询;请查阅to consult:查阅;参考;咨询;向Consult price:市场参考价格PYXIS CONSULT:峰仕咨询consult together:聚集磋商;共同计议BRG CONSULT:信息来源Investent consult:投资顾问Consult Office:资咨询一部consult bank:资信征询银行例句_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _1.V-T/V-I If you consult an expert or someone senior to you or consult with them, you ask them for their opinion, advice, or permission. 咨询2.V-T If you consult a book or a map, you look in it or look at it in order to find some information. 查阅3.V-RECIP If a person or group of people consults with other people or consults them, or if two people or groups consult , they talk and exchange ideas and opinions about what they might decide to do. 商量spy音标_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 英[spaɪ] 美[spaɪ]附加_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ [ 复数spies 过去式spied 过去分词spied 现在分词spying ]释义_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ vt. 侦察；发现；暗中监视vi. 侦察；当间谍n. 间谍；密探短语_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Spy Game:间谍游戏;特务游戏;间谍游戏专辑;谍战London Spy:伦敦谍影;伦敦间谍WATCH SPY:探表;饰尚City Spy:城市特务;阿鹤作品;都市奸细Remote Spy:远程间谍;远程消息监视程序;近程特务Spy Papa:间谍爸爸love spy:爱的间谍;爱的;情谍Spy MyeongWol:间谍明月例句_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _1.N-COUNT A spy is a person whose job is to find out secret information about another country or organization.间谍2.ADJ A spy satellite or spy plane obtains secret information about another country by taking photographs from the sky. 承担间谍任务的(卫星、飞机) [ADJ n]3.V-I Someone who spies for a country or organization tries to find out secret information about another country or organization. (为某国、某组织) 从事间谍活动4.spying N-UNCOUNT 从事间谍活动5.V-I If you spy on someone, you watch them secretly. 秘密监视scurvy音标_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 英[’skɜːvɪ] 美[’skɝvi]附加_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ [ 比较级scurvier 最高级scurviest ]释义_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ n. 坏血病adj. 卑鄙的，下流的；不中用的短语_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ scurvy rickets:坏血病性佝偻病;翻译scurvy weed:对坏血病有特效的alpine scurvy:糙皮病;翻译Scurvy seadogs:坏血病海狗scurvy detail:坏血病紫癜nautical scurvy:船员坏血病rickets scurvy:坏血病性佝偻病scurvy cress:陆生水芹例句_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 1.N-UNCOUNT Scurvy is a disease that is caused by a lack of vitamin C. 坏血病sugary音标_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 英[’ʃʊg(ə)rɪ] 美[’ʃʊɡəri]附加_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ [ 比较级sugarier 最高级sugariest ]释义_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ adj. 含糖的；甜的；糖状的；甜言蜜语的短语_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ sugary words:媚人的语言Sugary Trap:甜蜜陷阱blood sugary:血糖A Sugary:含糖Sugary Foods:含糖类食物Sugary Products:含糖食物SUGARY LIFE:小康生活sugary endosperm:糖质胚乳Sugary cut:切边粗糙例句_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 1.ADJ Sugary food or drink contains a lot of sugar. 含糖量高的[usu ADJ n]barbecue音标_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 英[’bɑːbɪkjuː] 美[’bɑrbɪkju]附加_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ [ 过去式barbecued 过去分词barbecued 现在分词barbecuing ]释义_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ n. 烤肉；吃烤肉的野宴vt. 烧烤；烤肉短语_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Mongolian barbecue:蒙古烤肉;唱片名Korea barbecue:韩国烧烤human barbecue:人肉烧烤;唱片名Barbecue Set:烧烤餐具;烧烤器具barbecue pit:烧烤炉barbecue brawl:烤肉宴风波Barbecue Franchise:烧烤加盟Barbecue fun:烧烤用具例句_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _1.N-COUNT A barbecue is a piece of equipment which you use for cooking on in the open air. (户外使用的) 烤架2.N-COUNT If someone has a barbecue , they cook food on a barbecue in the open air. 烧烤3.V-T If you barbecue food, especially meat, you cook it on a barbecue. (用烤架) 烧烤pea音标_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 英[piː] 美[pi]附加_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ [ 复数peas pease ]释义_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ n. 豌豆n. (Pea)人名；(意)佩亚短语_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Pea Cake:豌豆黄Pigeon Pea:木豆;树豆Pea Agar:豌豆琼脂;PEA琼脂Pea Pod:豌豆荚;豌豆夹;荷仁豆colorful pea:杂色豌豆;正色豌豆pea structure:豌豆状结构pea sprout:豆苗;豌豆芽;豌豆芽苗Little Pea:小豌豆;快乐的小豆子pea shingle:豆粒砾石例句_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _1.N-COUNT Peas are round green seeds that grow in long thin cases and are eaten as a vegetable. 豌豆balanced diet释义_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 均衡饮食短语_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ balanced d diet:均衡伙食;平衡膳食;平衡饮食balanced vegetarian diet:素食平衡;均衡的素食;平衡的素食饮食;平衡素食balanced-diet:平衡膳食balanced E diet:平衡饮食well-balanced daily diet:平衡的日常饮食keep a balanced diet:保持平衡饮食;保持均衡饮食;保持饮食平衡;良好的饮食习惯offer a balanced diet:提供平衡膳食advise a balanced diet:建议Balanced diet display area:平衡膳食展示区bean音标_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _英[biːn] 美[bin]释义_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _n. 豆；嘴峰；毫无价值的东西vt. 击…的头部n. (Bean)人名；(英)比恩短语_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _Coffee Bean:咖啡豆;香啡缤;豆角;咖啡豆色French bean:法国菜豆;扁豆;法国四季豆bean vermicelli:粉丝;龙口粉丝common bean:菜豆;普通菜豆;刀豆bean huller:豆类脱壳机;豆类去荚机;豆类脱荚机Bean Pole:滨波;自行车;宾波;高佬Bean Bar:宾达咖啡;宾bean meal:豆类粗粉例句_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _1.N-COUNT Beans such as green beans , French beans , or fava beans are the seeds of a climbing plant or the long thin cases which contain those seeds. 豆; 豆荚2.N-COUNT Beans such as soybeans and kidney beans are the dried seeds of other types of bean plants. 干豆3.N-COUNT Beans such as coffee beans or cocoa beans are the seeds of plants that are used to produce coffee, cocoa, and chocolate. (供制作咖啡、可可等饮料的) 豆形种子carrot音标_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _英[’kærət] 美[’kærət]释义_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _n. 胡萝卜诱饵短语_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _carrot juice:胡萝卜汁;红萝卜汁;甘笋汁;太空摇滚Carrot cake:胡萝卜蛋糕;红萝卜蛋糕;甘笋饼;萝卜糕Carrot Seed:胡萝卜籽;胡萝卜籽精油;胡萝卜种子;胡萝卜Carrot Powder:胡萝卜粉;胡萝卜粉末Carrot family:伞形花科;芹菜科;香芹科;伞形科Piere Carrot:皮尔·卡丹;皮尔卡丹Carrot see:胡萝卜籽精油ALMOND CARROT:杏仁胡萝卜Carrot Toner:胡萝卜纯净美颜柔肤水例句_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _1.N-VAR Carrots are long, thin, orange-coloured vegetables. They grow under the ground, and have green shoots above the ground. 胡萝卜2.N-COUNT Something that is offered to people in order to persuade them to do something can be referred to as a carrot . Something that is meant to persuade people not to do something can be referred to in the same sentence as a "stick." 诱饵。

基于FPGA的流水线单精度浮点数乘法器设计

基于FPGA的流水线单精度浮点数乘法器设计彭章国;张征宇;王学渊;赖瀚轩;茆骥【摘要】针对现有的采用Booth算法与华莱士(Wallace)树结构设计的浮点乘法器运算速度慢、布局布线复杂等问题,设计了基于FPGA的流水线精度浮点数乘法器.该乘法器采用规则的Vedic算法结构,解决了布局布线复杂的问题;使用超前进位加法器(Carry Look-ahead Adder,CLA)将部分积并行相加,以减少路径延迟;并通过优化的4级流水线结构处理,在Xilinx(R)ISE 14.7软件开发平台上通过了编译、综合及仿真验证.结果证明,在相同的硬件条件下,本文所设计的浮点乘法器与基4-Booth算法浮点乘法器消耗时钟数的比值约为两者消耗硬件资源比值的1.56倍.【期刊名称】《微型机与应用》【年(卷),期】2017(036)004【总页数】5页(P74-77,83)【关键词】浮点乘法器;超前进位加法器;华莱士树;流水线结构;Vedic算法;Booth 算法【作者】彭章国;张征宇;王学渊;赖瀚轩;茆骥【作者单位】西南科技大学信息工程学院,四川绵阳621010;西南科技大学信息工程学院,四川绵阳621010;中国空气动力研究与发展中心,四川绵阳621000;西南科技大学信息工程学院,四川绵阳621010;西南科技大学信息工程学院,四川绵阳621010;西南科技大学信息工程学院,四川绵阳621010【正文语种】中文【中图分类】TP331.2浮点乘法器(eFloating Point Multiplier，FPM)是数字信号处理(eDigital Signal Processing，DSP)、视频图像处理以及信号识别等应用邻域重要的运算单元。

尤其是在视频图像处理领域，随着对高速海量图像数据处理的实时性要求逐渐提高，设计一种具有更高速率、低功耗、布局规律、占用面积小和集成度高的浮点乘法器极其重要。

阵列乘法器是采用移位与求和的算法而设计的一种乘法器[1]。

2009_Design of low-power high-speed truncation-error-tolerant adder(J.IEEE)

This document is downloaded from DR-NTU, Nanyang TechnologicalUniversity Library, Singapore.Design of Low-Power High-SpeedTruncation-Error-Tolerant Adder and ItsApplication in Digital Signal ProcessingNing Zhu,Wang Ling Goh,Weija Zhang,Kiat Seng Yeo,andZhi Hui KongAbstract—In modern VLSI technology,the occurrence of all kinds of errors has become inevitable.By adopting an emerging concept in VLSI design and test,error tolerance(ET),a novel error-tolerant adder(ETA) is proposed.The ETA is able to ease the strict restriction on accuracy,and at the same time achieve tremendous improvements in both the power consumption and speed performance.When compared to its conventional counterparts,the proposed ETA is able to attain more than65%im-provement in the Power-Delay Product(PDP).One important potential application of the proposed ETA is in digital signal processing systems that can tolerate certain amount of errors.Index Terms—Adders,digital signal processing(DSP),error tolerance, high-speed integrated circuits,low-power design,VLSI.I.I NTRODUCTIONIn conventional digital VLSI design,one usually assumes that a us-able circuit/system should always provide deﬁnite and accurate results. But in fact,such perfect operations are seldom needed in our nondigital worldly experiences.The world accepts“analog computation,”which generates“good enough”results rather than totally accurate results[1]. The data processed by many digital systems may already contain er-rors.In many applications,such as a communication system,the analog signal coming from the outside world mustﬁrst be sampled before being converted to digital data.The digital data are then processed and transmitted in a noisy channel before converting back to an analog signal.During this process,errors may occur anywhere.Furthermore, due to the advances in transistor size scaling,factors such as noise and process variations which are previously insigniﬁcant are becoming im-portant in today’s digital IC design[2].Based on the characteristic of digital VLSI design,some novel con-cepts and design techniques have been proposed.The concept of error tolerance(ET)[3]–[10]and the PCMOS technology[11]–[13]are two of them.According to the deﬁnition,a circuit is error tolerant if:1)it contains defects that cause internal and may cause external errors and2)the system that incorporates this circuit produces acceptable results[3].The“imperfect”attribute seems to be not appealing.However,the need for the error-tolerant circuit[3]–[10]was foretold in the2003In-ternational Technology Roadmap for Semiconductors(ITRS)[2].To deal with error-tolerant problems,some truncated adders/multi-pliers have been reported[14],[15]but are not able to perform well in either its speed,power,area,or accuracy.The“ﬂagged preﬁxed adder”[14]performs better than the nonﬂagged version with a1.3%speed enhancement but at the expense of2%extra silicon area.As for the “low-error area-efﬁcientﬁxed-width multipliers”[15],it may have an area improvement of46.67%but has average error reaching12.4%. Of course,not all digital systems can engage the error-tolerant con-cept.In digital systems such as control systems,the correctness of the output signal is extremely important,and this denies the use of the error-tolerant circuit.However,for many digital signal processing (DSP)systems that process signals relating to human senses such as Manuscript received May28,2008;revised February12,2009.The authors are with the School of Electrical and Electronic Engineering, Nanyang Technological University,Singapore,639798(e-mail:zhuning@ntu. edu.sg).Digital Object Identiﬁer10.1109/TVLSI.2009.2020591hearing,sight,smell,and touch,e.g.,the image processing and speechprocessing systems,the error-tolerant circuits may be applicable[3],[6],[7].The rest of the paper is organized as follows.Section II proposes theaddition arithmetic as well as the structure of the error-tolerant adder(ETA).In Section III,the detailed design of the ETA is explained.Theexperimental results are shown in Section IV.Section V provides anapplication example of the stly,the conclusion of this work ispresented in Section VI.II.E RROR-T OLERANT A DDERBefore detailing the ETA,the deﬁnitions of some commonly usedterminologies shown in this paper are given as follows.•Overall error(OE):OE=j R c0R e j,where R e is the result obtained by the adder,and R c denotes the correct result(all theresults are represented as decimal numbers).•Accuracy(ACC):In the scenario of the error-tolerant design,theaccuracy of an adder is used to indicate how“correct”the outputof an adder is for a particular input.It is deﬁned as:ACC= (10(OE=R c))2100%.Its value ranges from0%to100%.•Minimum acceptable accuracy(MAA):Although some errors are allowed to exist at the output of an ETA,the accuracy of an ac-ceptable output should be“high enough”(higher than a threshold value)to meet the requirement of the whole system.Minimum ac-ceptable accuracy is just that threshold value.The result obtained whose accuracy is higher than the minimum acceptable accuracy is called acceptable result.•Acceptance probability(AP):Acceptance probability is the prob-ability that the accuracy of an adder is higher than the minimumacceptable accuracy.It can be expressed as AP=P(ACC> MAA),with its value ranging from0to1.A.Need for Error-Tolerant AdderIncreasingly huge data sets and the need for instant response re-quire the adder to be large and fast.The traditional ripple-carry adder (RCA)is therefore no longer suitable for large adders because of its low-speed performance.Many different types of fast adders,such as the carry-skip adder(CSK)[16],carry-select adder(CSL)[17],and carry-look-ahead adder(CLA)[18],have been developed.Also,there are many low-power adder design techniques that have been proposed [19].However,there are always trade-offs between speed and power. The error-tolerant design can be a potential solution to this problem. By sacriﬁcing some accuracy,the ETA can attain great improvement in both the power consumption and speed performance.B.Proposed Addition ArithmeticIn a conventional adder circuit,the delay is mainly attributed to the carry propagation chain along the critical path,from the least signif-icant bit(LSB)to the most signiﬁcant bit(MSB).Meanwhile,a sig-niﬁcant proportion of the power consumption of an adder is due to the glitches that are caused by the carry propagation.Therefore,if the carry propagation can be eliminated or curtailed,a great improvement in speed performance and power consumption can be achieved.In this paper,we propose for theﬁrst time,an innovative and novel addition arithmetic that can attain great saving in speed and power consumption. This new addition arithmetic can be illustrated via an example shown in Fig.1.Weﬁrst split the input operands into two parts:an accurate part that includes several higher order bits and the inaccurate part that is made up of the remaining lower order bits.The length of each part need not necessary be equal.The addition process starts from the middle1063-8210/$26.00©2009IEEEFig.1.Proposed additionarithmetic.Fig.2.Relationship between AP and MAA.(joining point of the two parts)toward the two opposite directions si-multaneously.In the example of Fig.1,the two 16-bit input operands,A =“1011001110011010”(45978)and B =“0110100100010011”(26899),are divided equally into 8bits each for the accurate and inac-curate parts.The addition of the higher order bits (accurate part)of the input operands is performed from right to left (LSB to MSB)and normal addition method is applied.This is to preserve its correctness since the higher order bits play a more important role than the lower order bits.The lower order bits of the input operands (inaccurate part)re-quire a special addition mechanism.No carry signal will be generated or taken in at any bit position to eliminate the carry propagation path.To minimize the overall error due to the elimination of the carry chain,a special strategy is adapted,and can be described as follow:1)check every bit position from left to right (MSB to LSB);2)if both input bits are “0”or different,normal one-bit addition is performed and the operation proceeds to next bit position;3)if both input bits are “1,”the checking process stopped and from this bit onward,all sum bits to the right are set to “1.”The addition mechanism described can be easily understood from the example given in Fig.1with a ﬁnal result of “10001110010011111”(72863).The example given in Fig.1should actually yield “10001110010101101”(72877)if normal arithmetic has been applied.The overall error generated can be com-puted as OE =72877072863=14.The accuracy of the adder with respect to these two input operands is ACC =(10(14=72877))2100%=99:98%.Fig.3.Relationship between AP and size ofadder.Fig.4.Hardware implementation of the proposed ETA.By eliminating the carry propagation path in the inaccurate part and performing the addition in two separate parts simultaneously,the overall delay time is greatly reduced,so is the power consumption.C.Relationships Between Minimum Acceptable Accuracy,Acceptance Probability,Dividing Strategy,and Size of Adder The accuracy of the adder is closely related to the input pattern.As-sume that the input of an adder is random;there exists a probability that we can obtain an acceptable result (i.e.,the acceptance proba-bility).The accuracy attribute of an ETA is determined by the dividing strategy and size of adder.In this subsection,the relationships between the minimum acceptable accuracy,the acceptance probability,the di-viding strategy,and the size of adder are investigated.We ﬁrst consider the extreme situation where we accept only the perfectly correct result.The minimum acceptable accuracy in this “per-fect”situation is 100%.According to the proposed addition arithmetic,we can obtain correct results only when the two input bits on every po-sition in the inaccurate part are not equal to “1”at the same time.We can therefore derive an equation to calculate the acceptance probability associated with the proposed ETA with different bit sizes and dividing strategies.This equation is given as follows:P (ACC =100%)=4N0N23N +2N 0N4N +2N(1)where N t is the total number of bits in the input operand (also regarded as the size of the adder)and N l is the number of bits in the inaccurate part (which is indicating the dividing strategy).Fig.5.Carry-free addition block.(a)Overall architecture and(b)schematic diagram of a modiﬁed XOR gate.In situations where the requirement on accuracy can be somewhat re-laxed are investigated,the result will be different.C program is engaged to simulate a16-bit adder that had adopted the proposed addition mech-anism.By checking the output results,we can derive the relationship between the minimum acceptable accuracy and acceptance probability, as depicted in Fig.2.The four curves represent four different dividing strategies,and each of which has been assigned a name“N0M”where “N”denotes the size of the accurate part and“M”for the size of the inaccurate part.For the input patterns,we randomly select10000in-puts from all possible input patterns(i.e.,0–65535).It can be deduced from Fig.2that the lower the minimum acceptable accuracy set,the higher the acceptance probability for the adder.Fig.2also shows that different dividing strategies lead to different accuracy performance. As modern VLSI technology advances,the size of the adder has to in-crease to cater to the application need.The trend of the accuracy perfor-mance of an ETA is therefore investigated in Fig.3.Theﬁve curves are associated with different minimum acceptable accuracies,95%,96%, 97%,98%,and99%,respectively.Note that all adders follow the same dividing strategy whereby the inaccurate part is three times larger than that of the accurate part.Since small numbers will be calculated at the inaccurate part of the adder,the proposed ETA is best suited for large input patterns.D.Hardware ImplementationThe block diagram of the hardware implementation of such an ETA that adopts our proposed addition arithmetic is provided in Fig.4.This most straightforward structure consists of two parts:an accurate part and an inaccurate part.The accurate part is constructed using a con-ventional adder such as the RCA,CSK,CSL,or CLA.The carry-in of this adder is connected to ground.The inaccurate part constitutes two blocks:a carry-free addition block and a control block.The control block is used to generate the control signals,to determine the working mode of the carry-free addition block.In Section III,a32-bit adder is used as an example for our illustration of the design methodology and circuit implementation of an ETA.III.D ESIGN OF A32-B IT E RROR-T OLERANT A DDERA.Strategy of Dividing the AdderTheﬁrst step of designing a proposed ETA is to divide the adder into two parts in a speciﬁc manner.The dividing strategy is based on a guess-and-verify stratagem,depending on the requirements,such as accuracy,speed,and power.First,we deﬁne the delay of the proposed adder as T d= max(T h;T l),where T h is the delay in the accurate part and T l is the delay in the inaccurate part.With the proper dividing strategy, we can make T h approximately equal to T l and hence achieve an optimal time delay.With this partition method deﬁned,we then check whether the ac-curacy performance of the adder meets the requirements preset by de-signer/customer.This can be checked very quickly via some software programs.For example,for a speciﬁc application,we require the min-imum acceptable accuracy to be95%and the acceptance probability to be98%.The proposed partition method must therefore have at least 98%of all possible inputs reaching an accuracy of better than95%.If this requirement is not met,then one bit should be shifted from the inac-curate part to the accurate part and have the checking process repeated. Also,due to the simpliﬁed circuit structure and the elimination of switching activities in the inaccurate part,putting more bits in this part yields more power saving.Having considered the above,we divided the32-bit adder by putting 12bits in the accurate part and20bits in the inaccurate part.B.Design of the Accurate PartIn our proposed32-bit ETA,the inaccurate part has20bits as op-posed to the12bits used in the accurate part.The overall delay is de-termined by the inaccurate part,and so the accurate part need not be a fast adder.The ripple-carry adder,which is the most power-saving conventional adder,has been chosen for the accurate part of the circuit.C.Design of the Inaccurate PartThe inaccurate part is the most critical section in the proposed ETA as it determines the accuracy,speed performance,and power consump-Fig.6.Control block.(a)Overall architecture and(b)schematic implementations of CSGC.tion of the adder.The inaccurate part consists of two blocks:the carry-free addition block and the control block.The carry-free addition block is made up of20modiﬁed XOR gates,and each of which is used to gen-erate a sum bit.The block diagram of the carry-free addition block and the schematic implementation of the modiﬁed XOR gate are pre-sented in Fig.5.In the modiﬁed XOR gate,three extra transistors,M1, M2,and M3,are added to a conventional XOR gate.CTL is the con-trol signal coming from the control block of Fig.6and is used to set the operational mode of the circuit.When CTL=0,M1and M2are turned on,while M3is turned off,leaving the circuit to operate in the normal XOR mode.When CTL=1,M1and M2are both turned off, while M3is turned on,connecting the output node to VDD,and hence setting the sum output to“1.”The function of the control block is to detect theﬁrst bit position when both input bits are“1,”and to set the control signal on this po-sition as well as those on its right to high.It is made up of20con-trol signal generating cells(CSGCs)and each cell generates a control signal for the modiﬁed XOR gate at the corresponding bit position in the carry-free addition block.Instead of a long chain of20cascaded GSGCs,the control block is arranged intoﬁve equal-sized groups,with additional connections between every two neighboring groups.Two types of CSGC,labeled as type I and II in Fig.6(a),are designed,and the schematic implementations of these two types of CSGC are pro-vided in Fig.6(b).The control signal generated by the leftmost cell of each group is connected to the input of the leftmost cell in next group.The extra connections allow the propagated high control signal to“jump”from one group to another instead of passing through all the20cells.Hence,the worst case propagation path[shaded in gray in Fig.6(a)]consists of only ten cells.IV.E XPERIMENTAL R ESULTSTo demonstrate the advantages of the proposed ETA,we simulated the ETA along with four types of conventional adders,i.e.,the RCA, CSK,CSL,and CLA,using HSPICE.All the circuits were imple-mented using Chartered Semiconductor Manufacturing Ltd’s0.18- m CMOS process.The input frequency was set to100MHz,and the sim-ulation results are all tabulated in Table I.HSPICE software was used to construct the models of our proposed ETA and the conventional adders.100sets of inputs were randomly cre-ated using the C program“random()”function.For each set of input,weTABLE IS IMULATION R ESULT FOR ETA V ERSUS C ONVENTIONAL ADDERSran the simulation for each adder and recorded the power consumption. With100sets of results,average power consumption was determined. The worst case input was calculated and used to simulate the delay. The transistor count was derived directly from the HSPICE software. Comparing the simulation results of our proposed ETA with those of the conventional adders(see Table I),it is evident that the ETA per-formed the best in terms of power consumption,delay,and Power-Delay Product(PDP).The PDP of the ETA is noted to be66.29%, 77.44%,83.70%,and75.21%better than the RCA,CSK,CSL,and CLA,respectively.As for transistor count,the proposed ETA is almost as good as the RCA.V.A PPLICATION OF E RROR-T OLERANT A DDERIN D IGITAL S IGNAL P ROCESSINGIn image processing and many other DSP applications,fast Fourier transformation(FFT)is a very important function.The computational process of FFT involves a large number of additions and multiplica-tions.It is therefore a good platform for embedding our proposed ETA. To prove the feasibility of the ETA,we replaced all the common addi-tions involved in a normal FFT algorithm with our proposed addition arithmetic.As we all know,a digital image is represented by a matrix in a DSP system,and each element of the matrix represents the color of one pixel of the image.To compare the quality of images processed by both the conventional FFT and the inaccurate FFT that had incorporated our proposed ETA,we devised the following experiment.An image was ﬁrst translated to a matrix form and sent through a standard system that made used of normal FFT and normal reverse FFT.The matrix output of this system was then transformed back to an image and presented in Fig.7(a).The matrix of the same image was also processed in a systemFig.7.Images after FFT and inverse FFT.(a)Image processed with conven-tional adder and(b)image processed with the proposed ETA.that used the inaccurate FFT and inaccurate reverse FFT,where both FFTs had incorporated the32-bit ETA described in Section III,with the processed image given in Fig.7(b).Although the two resultant matrices of the same image were dif-ferent,the two pictures obtained(see Fig.7)look almost the same. Fig.7(b)is slightly darker and contains horizontal bands of different shades of gray.With a MAA setting of95%,the AP of the matrix repre-sentation of Fig.7(b)is98.3%as compared to the matrix representation of Fig.7(a).The comparison between the two images in Fig.7shows that the quality loss to the image using our proposed ETA is negligible and can be completely tolerated by human eyes.These simulation results have proven the practicability of the ETA proposed in this paper.VI.C ONCLUSIONIn this paper,the concept of error tolerance is introduced in VLSI de-sign.A novel type of adder,the error-tolerant adder,which trades cer-tain amount of accuracy for signiﬁcant power saving and performance improvement,is proposed.Extensive comparisons with conventional digital adders showed that the proposed ETA outperformed the conven-tional adders in both power consumption and speed performance.The potential applications of the ETA fall mainly in areas where there is no strict requirement on accuracy or where superlow power consumption and high-speed performance are more important than accuracy.One example of such applications is in the DSP application for portable de-vices such as cell phones and laptops.A CKNOWLEDGMENTW.Zhang would like to thank the Nanyang Technological University (NTU)of Singapore for providing the graduate research scholarship and support.The authors appreciate also the help rendered by Mr.L. Y.Loy.R EFERENCES[1]A.B.Melvin,“Let’s think analog,”in Proc.IEEE Comput.Soc.Annu.Symp.VLSI,2005,pp.2–5.[2]International Technology Roadmap for Semiconductors[Online].Available:/[3]A.B.Melvin and Z.Haiyang,“Error-tolerance and multi-media,”in Proc.2006Int.Conf.Intell.Inf.Hiding and Multimedia SignalProcess.,2006,pp.521–524.[4]M.A.Breuer,S.K.Gupta,and T.M.Mak,“Design and error-toler-ance in the presence of massive numbers of defects,”IEEE Des.TestComput.,vol.24,no.3,pp.216–227,May-Jun.2004.[5]M.A.Breuer,“Intelligible test techniques to support error-tolerance,”in n Test Symp.,Nov.2004,pp.386–393.[6]K.J.Lee,T.Y.Hsieh,and M.A.Breuer,“A novel testing methodologybased on error-rate to support error-tolerance,”in Proc.Int.Test Conf.,2005,pp.1136–1144.[7]I.S.Chong and A.Ortega,“Hardware testing for error tolerant mul-timedia compression based on linear transforms,”in Proc.Defect andFault Tolerance in VLSI Syst.Symp.,2005,pp.523–531.[8]H.Chung and A.Ortega,“Analysis and testing for error tolerant motionestimation,”in Proc.Defect and Fault Tolerance in VLSI Syst.Symp.,2005,pp.514–522.[9]H.H.Kuok,“Audio recording apparatus using an imperfect memorycircuit,”U.S.Patent5414758,May9,1995.[10]T.Y.Hsieh,K.J.Lee,and M.A.Breuer,“Reduction of detected ac-ceptable faults for yield improvement via error-tolerance,”in Proc.Des.,Automation and Test Eur.Conf.Exhib.,2007,pp.1–6.[11]K.V.Palem,“Energy aware computing through probabilisticswitching:A study of limits,”IEEE put.,vol.54,no.9,pp.1123–1137,Sep.2005.[12]S.Cheemalavagu,P.Korkmaz,and K.V.Palem,“Ultra low energycomputing via probabilistic algorithms and devices:CMOS deviceprimitives and the energy-probability relationship,”in Proc.2004Int.Conf.Solid State Devices and Materials,Tokyo,Japan,Sep.2004,pp.402–403.[13]P.Korkmaz,B.E.S.Akgul,K.V.Palem,and L.N.Chakrapani,“Advo-cating noise as an agent for ultra-low energy computing:Probabilisticcomplementary metal-oxide-semiconductor devices and their charac-teristics,”Jpn.J.Appl.Phys.,vol.45,no.4B,pp.3307–3316,2006.[14]J.E.Stine,C.R.Babb,and V.B.Dave,“Constant addition utilizingﬂagged preﬁx structures,”in Proc.IEEE Int.Symp.Circuits and Sys-tems(ISCAS),2005.[15]L.-D.Van and C.-C.Yang,“Generalized low-error area-efﬁcientﬁxed-width multipliers,”IEEE Trans.Circuits Syst.I,Reg.Papers,vol.25,no.8,pp.1608–1619,Aug.2005.[16]M.Lehman and N.Burla,“Skip techniques for high-speed carry prop-agation in binary arithmetic units,”IRE put.,vol.EC-10,pp.691–698,Dec.1962.[17]O.Bedrij,“Carry select adder,”IRE put.,vol.EC-11,pp.340–346,1962.[18]O.MacSorley,“High speed arithmetic in binary computers,”IRE Proc.,vol.49,pp.67–91,1961.[19]Y.Kiat-Seng and R.Kaushik,Low-Voltage,Low-Power VLSI Subsys-tems.New York:McGraw-Hill,2005.。

基于改进五输入择多门的QCA全加器设计及应用

基于改进五输入择多门的QCA全加器设计及应用刘帅;解光军;张永强;项云龙;吕洪君【摘要】Quantum-dot cellular automata (QCA) is an emerging nanotechnology .A full adder based on improved five-input majority gate is proposed .The full adder keeps correct logic function and dominates the previous results .Then it is applied to imple-ment adder andmultiplier .Results illustrate that they improve significantly in some performance .%量子元胞自动机（Quantum-dot cellular automata ，QCA ）是一种新兴的纳米技术。

本文基于改进的五输入择多门，设计出一个全加器，在保持正确逻辑功能的基础上较以往的全加器有一定优势。

应用该全加器设计加法器和乘法器，结果表明在某些性能上有显著提高。

【期刊名称】《电子学报》【年(卷),期】2015(000)002【总页数】6页(P387-392)【关键词】量子元胞自动机;五输入择多门;全加器;加法器;乘法器【作者】刘帅;解光军;张永强;项云龙;吕洪君【作者单位】合肥工业大学电子科学与应用物理学院，安徽合肥230009;合肥工业大学电子科学与应用物理学院，安徽合肥230009;合肥工业大学电子科学与应用物理学院，安徽合肥230009;合肥工业大学电子科学与应用物理学院，安徽合肥230009;合肥工业大学电子科学与应用物理学院，安徽合肥230009【正文语种】中文【中图分类】TN4021 引言随着晶体管技术的提高，器件尺寸越来越小，小尺寸效应逐渐显现出来，严重影响器件的性能，因此需要有新的技术来取代CMOS.Lent等［1］1993年第一次提出量子元胞自动机，基于QCA的电路具有高速、高集成度以及低功耗［2］等优点，能够解决传统CMOS器件的一些问题，因而获得广泛关注.全加器在数字电路中的重要性，使得其在QCA电路中获得比较多的研究.本文在改进五输入择多门的基础上，设计出一个全加器，该全加器在保持最小输出延迟的基础上，减少了元胞使用数目及占用面积，同时具有更高的稳定性.为了进一步探讨该全加器的性能，应用其设计加法器和乘法器.结果表明，均具有正确的逻辑功能，而且性能更加优越.2 量子元胞自动机原理2.1 QCA元胞QCA元胞由处于正方形顶点的四个量子点和两个可以自由移动的电子组成，由于库仑作用，电子只有处于对角线上的量子点时才能达到稳定状态，分别对应极化状态P=－1和P=1，如图1所示.定义当P=－1时对应二进制信息0，当P=1时对应二进制信息1.2.2 时钟时钟主要有两方面的作用:(1)同步控制信息传输;(2)提供电路所需能量［3］.通常用四个相位差为90°的时钟来控制信息的传输，用四种不同颜色来区分表示，信息传输顺序为时钟0→时钟1→时钟2→时钟3，如图2所示.2.3 逻辑单元在QCA电路中最基本的逻辑单元是反相器和择多门.反相器如图3(a)所示;择多门主要有两种，一种是三输入择多门，一种是五输入择多门.三输入择多门如图3(b)所示.第一种五输入择多门由Azghadi等［4］提出，它由三维的元胞构成，但并不能应用到电路中;Navi等［5，6］提出两种择多门，文献［5］中的输出端位于内部，没有实用性;文献［6］中的由10个元胞构成，元胞用一个时钟控制;Akeela等［7］提出一种择多门，Hashemi等［8］提出两种择多门，但这三种使用的元胞比较多，而且都要用三个时钟控制.如图4所示(图4(d)，(e)，(f)中不同颜色的元胞表示处于不同的时钟).3 全加器设计3.1 改进的五输入择多门为了减少全加器的元胞数目、缩小面积，将图4(c)中的五输入择多门作出改进，如图5所示.在图4(c)中，元胞E作为一个输入端.在改进后，去掉元胞E，在原来的位置放置一个正常元胞，并且增加一个正常元胞使其与输入端C相连.这样，输入端C便起到两个输入端的作用，正好符合由五输入择多门构成的全加器中进位信号的需求，极大的简化了电路走线.另外，只有当输入信号同时进入具有表决作用的元胞时，择多门才能保持正确功能.因此，为了保证输出正确，输出端F以及中间四个元胞都用时钟1来控制.3.2 全加器数字电路中算术运算(加、减、乘、除)最终都可归结为加法运算，所以加法器的设计尤为重要，而全加器又是加法器的基础，因此性能优越的全加器有着举足轻重的作用.第一种全加器由Lent等［9］提出来，由五个三输入择多门和三个反相器组成，后来Wang等［10］将全加器“和”的表达式简化，逻辑结构随之缩减到三个三输入择多门和两个反相器.Cho等［11］在此基础上设计出一种全加器，元胞数目为86，“和”输出延迟周期，进位输出延迟周期.最近，Pudi等［12］进一步将全加器简化，只用到三个三输入择多门和一个反相器.我们提出的全加器，由一个三输入择多门、一个五输入择多门和一个反相器组成，逻辑表达式为其中A、B、C分别为加数和被加数以及进位输入，CO为进位输出，S为和.该全加器的结构图、元胞图及仿真结果如图6所示.该全加器由66个元胞构成，“和”输出与进位输出.与 Cho等［11］设计的全加器相比，在输出延迟保持一致的情况下，元胞数目减少了20;与 Pudi等［12］相比，进位输出延迟保持一致，“和”输周期.而且由于输出端不被其它元胞所包围，该全加器具有良好的扩展性.目前，也有文献提出以五输入择多门构成的全加器，如Navi等［6］设计的全加器由73个元胞组成，输出延迟与本文的全加器一致，但是由于该全加器的三个输入端位于全加器的内部，导致不具备可扩展性.Hashemi等［8］设计出两种全加器，其中一种虽然使用更少的元胞，但电路中的反相器不稳定，电路稳定性差，并且扩展性也不好;另外一种全加器使用79个元胞，输出延迟个周期，与本文全加器相比，输出延迟大大增加.3.3 全加器的稳定性元胞缺失、移位等缺陷会对电路的稳定性造成影响，本文设计的全加器和Pudi等［12］设计的全加器在结构上相似，可以通过概率转移矩阵［13］比较二者的稳定性.对于有m个输入、n个输出的电路，共有2m×2n种输入和输出组合，每种输入对应1种正确输出和2n－1种错误输出.假设正确的输出概率为p，每种错误输出概率相等且总和为q，则p+q=1.根据上述描述可以列出不同单元的概率转移矩阵，如下所示假设有两个逻辑单元A和B，概率转移矩阵分别为TA和TB.若A的输出为B的输入，则二者称为串联结构，总的概率转移矩阵为TA·TB;若A与B互不影响，则二者称为并联结构［14］，总的概率转移矩阵为TA⊗TB(运算符和⊗的定义与文献［14］一致).Pudi等［12］设计的全加器和本文的全加器结构分别如图7(a)、(b)所示.图中虚线框为两种全加器的不同部分，由于其它部分相同，可以通过虚线框内的对比来计算两种全加器的稳定性，即基于上述表达式得出总体错误率Q随错误概率q的变化曲线，如图8所示.由上图可知，在错误概率q相等的情况下，图7(b)的总体错误率要比图7(a)小，因此图7(b)中的全加器稳定性更高，可以更好地应用到大规模的电路中.4 全加器的应用4.1 加法器Cho等［11］利用全加器设计出载流进位加法器(Carry Flow Adder，CFA)，Pudi等［12］利用其设计的全加器实现了脉冲进位加法器(Ripple Carry Adder，RCA).本文的全加器具有良好的扩展性，只需将前一个全加器的进位输出端连接到下一个全加器的进位输入端，便可实现加法器.限于篇幅，图9只给出四位加法器的元胞图和仿真结果.与上述两种加法器进行对比，结果如表1所示(本文的加法器用Proposed来代表，后面的数字代表加法器的位数).由上述对比可知，基于本文全加器实现的加法器在保持最小时钟延迟的基础上，无论是元胞数目还是面积都较另外两种有很大的优势，而且优势随着加法器位数的增加不断扩大.4.2 乘法器实现乘法器的关键在于乘法器网络的构造，Cho等基于滤波网络提出一个乘法器网络，在此基础上设计出进位延迟乘法器［11］(Carry Delay Multiplier，CDM).借助于该乘法器网络，本文的全加器也可以实现乘法器.首先将本文的全加器修改为内部进位全加器，如图10所示(图10(a)中D代表时钟延迟).根据乘法器网络，利用图10(b)所示内部进位全加器设计出乘法器.图11为四位乘法器的元胞图与仿真结果，输出延迟1个周期.将本文的乘法器与Cho等［11］设计的进位延迟乘法器进行对比，结果如表2所示(本文的乘法器用Multiplier表示，后面的数字代表乘法器的位数).表1 三种加法器的对比延迟Proposed4 279 0.58 ×0.24 0.139 1类型元胞数目长×宽(μm×μm)面积(μm2)clocks Proposed8 584 1.14 ×0.40 0.456 2 2 4clocks Proposed16 1356 2.26 ×0.56 1.266 4 2 4 clocks Proposed32 3476 4.50 ×0.88 3.960 8 2 4 clocks Proposed64 10020 8.98 ×1.54 13.829 16 2 4 clocks CFA4 371 0.90 ×0.45 0.405 1 2 4 clocks CFA8 789 1.79 ×0.53 0.948 2 2 4 clocks CFA16 1769 3.55 ×0.69 2.450 4 2 4 clocks CFA32 4305 7.09 ×1.303 7.300 8 2 4 clocks CFA64 11681 14.15 ×1.71 24.196 16 2 4 clocks RCA4 339 0.82 ×0.31 0.254 1 2 4 clocks RCA8 712 1.62×0.46 0.745 2 3 4 clocks RCA16 1602 3.22 ×0.62 1.996 4 3 4 clocks RCA32 3901 6.46 ×1.00 6.460 8 3 4 clocks RCA64 10926 12.9 ×1.66 20.916 16 3 43 4c locks表2 两种乘法器的对比延迟Multiplier 4 291 0.76 ×0.32 0.243 1clock Multiplier 8 679 1.68 ×0.34 0.571 1clock Multiplier16 1557 3.46 ×0.44 1.522 1clock Multiplier 32 3677 7.02 ×0.62 4.352 1clock Multiplier 64 9472 14.08 ×0.98 13.798 1clock CDM4 406 1.05 ×0.47 0.494 1clock CDM8 903 2.12 ×0.47 0.996 1clock CDM16 1999 4.19 ×0.47 1.9691clock CDM32 4575 8.47 ×0.65 5.506 1clock CDM64 11264 16.84 ×0.95 15.998 1clock类型元胞数目长×宽(μm×μm) 面积(μm2)通过对比可知，在输出延迟相同的情况下，本文的乘法器无论是元胞数目还是面积都较Cho等人设计的进位延迟乘法器有很大优势.5 结论本文在改进五输入择多门的基础上设计出一种全加器，该全加器具有正确的逻辑功能.在保持最小输出延迟的前提下，无论是元胞数目还是占用面积均较以往全加器有一定的减少，通过概率转移矩阵计算发现该全加器的结构更加稳定，有利于应用到大规模电路中.为进一步研究该全加器的性能，将其应用到加法器和乘法器中，结果表明，基于本文全加器实现的加法器和乘法器较以往使用更少的元胞，占用面积也进一步缩小，而且还保持最小的时钟延迟，因此性能更加优越.参考文献【相关文献】［1］C S Lent，P D Tougaw，W Porod.Bistable saturation in coupled quantum dots for quantum cellular 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并行前缀加法器的研究与实现

并行前缀加法器的研究与实现微电子学与计算机2005年第22卷第12期并行前缀加法器的研究与实现靳战鹏沈绪榜罗曼(西北工业大学计算机学院.陕西西安710072)摘要:随着微处理器运算速度的大幅度提高,对快速加法器的需求也越来越高.当VLSI工艺进入深亚微米阶段的时候,很多情况下,无论是在面积还是在时序上连线都起着决定性的作用.文章基于不同的CMOS工艺.针对三种不同结构的并行前缀加法器,在不同数据宽度的情况下进行性能比较.根据深亚微米下金属互连线对加法器性能的影响,挑选出适合深亚微米工艺的加法器结构.关键词:并行前缀加法器,KS结构,LF结构,BK结构中图法分类号:TF39文献标识码:A文章编号:1000—7180(2005)12—092—04 ResearchandImplementationofParallelPrefixAdderJINZhan—peng,SHENXu—bang,LUOMin(SchoolofComputerScience,NorthwesternPolytechnicalUniversity,Xi'an710072China) Abstract:Witlltllegreatincreaseofthespeedofmodernmicroprocessors.theneedoffastadde rsbecomesmoreexi.gent.Whenthetechnologyhasgotthestageofdeepsubmicron.theconnectivewirewillplaya nimportantroleeitherintheareaorinthetiming.BasedonvariousCMOStechnologies:O.181~m,O.151~m,O.131~ mand90nm,thisthesismakes aperformancecomparisonwithdifferentbitwidths,andthenselectstheadderarchitecturefitf ordeepsubmicrontech. nologyaccordingtotheimpactofconnectivewiresonadderperformanceindeepsubmicront echnology.Keywords:Parallelprefixadder,KSadder,LFadder,BKadder 1引言众所周知.在高性能微处理器和DSP处理器中.二进制加法器的运算时间至关重要,加法运算常常处于高性能处理器运算部件的关键路径中随着微处理器运算速度的大幅度提高.对快速加法器的需求也越来越高.因此,为了减少进位传输所耗的时间.提高计算速度,多年以来,人们提出了许多快速加法器结构.并且以不同的电路设计类型加以实现i1一.为了进一步提高加法器的运算速度.提出了并行前缀加法器(ParallelPrefixAdder)结构[3-5]由于采用了简单的标准单元以及规则的内部连接.并行前缀加法器非常适合于VLsI实现对于目前的并行前缀加法器而言.在逻辑层次已经最小的情况下.如何进一步提高加法器的性能是一个关键的问题.在影响性能的几个因素中.扇出(Fanout)和连线长度在其中起了关键作用当VLSI工艺进入深亚微米工艺阶段的时候.在很多情况下.连线的作用无论是在面积还是在时序上都起收稿日期:20o5—04—14基金项目:国防"十五"预研课题(41308010108)西北工业大学研究生创业种子基金(Z20040o5O)着决定性的作用[6一.因此,研究加法器中互连线的作用是非常有必要的本文基于不同的CMOS工艺:0.18m,0.15m,0.13m,以及90nm,针对三种不同结构的并行前缀加法器:LF结构[41,BK结构网,以及KS结构[3J.在不同数据宽度的情况下进行性能比较.根据深亚微米下金属互连线对加法器结构的影响.挑选出适合深亚微米工艺的加法器结构2并行前缀加法器对于并行前缀加法器,有如下定义:两个操作数A=aoa1..…a1.an_l'B=bob1...6.b.其中0<i<0—1,O<j<n一1.同时有操作:+6,.j}F+6l,pi=aiblO<i<n一1(1)定义前缀操作"?":()?()=()<(2)因此,加法进位可以表示为:(—Cnkn-lkk)=(卫k)(卫k)(卫k)卫kh\,….j}1o厂,?,,?,…()().(,nm(3)2005年第22卷第l2期微电子学与计算机93从式(1)～式(3)廿J以看出,日lJ缴加法器廿J以是一个级联进位加法器(ripplecalTyadder).但是由于前缀操作具有结合律(Associativity):(()¨?()?()J,=()¨?(()J?()『,h<i<j<k(4)其中,()=()?()?()?…?()J一让明如卜:(()¨?()?(,=(学).(铷=(舒)(6)()?(()?(=()?()一,岛.±墨!(臣止盘iJ:&l盘2,一,g±墨:臣.f±(盘!墨:臣&2, 一.j}^,磅,～kl,,.j}磅,:(啦)(7)一磅,前缀操作同时还具有冥等律(Idempotency),()¨=()¨?()h<k<i<j(8)证明如下:()?()=()蛐?(,.?()"?()=().(=(?()()=()蛐?()=()(9)但是前缀操作不支持交换率.证明如下:()?()『=()()『?()F()(10)以上两个鲁式不相等.根据结合律以及冥等律这两种重要的特性.可以将以上串行加法操作转化成为并行的加法操作.其中.结合律允许前缀等式中的每一个子项进行预计算.这也就意味着上面提到的串行计算可以被分解为多个并行计算的过程.同时,冥等律允许这些并行计算的子项相互之间可以重叠.这样就使并行计算具有很大的灵活性.目前.通常使用的并行前缀加法器有KS加法器[31,LF加法器网以及BK加法器【5】,这三种并行前缀加法器的结构分别如图l～图3所示.图1KS/JI]法器结构图2LFJJII法器结构图3BK~II法器结构在以上三种结构中.LF结构充分利用了前缀计算所具有的结合律特性.但是没有使用冥等律.图2 中显示了l6位加法器的每一级节点之间的互联关系输入在最顶层.输出在最低层,最高位在最左边图中仅仅显示了横向之间的联系,而没有显示纵向之间的联系在第一行中.每一个节点用来计算,p,k.在后面每行中,拥有横向连线的节点都是一个前缀计算节点最后一行用来计算加法的和.LF加法器结构具有最小的逻辑深度,但是同时也具有最大的扇出.在最后一级.最大扇出可以达到n,2.因此,对于LF加法器而言,连线长度与扇出成为影响延迟的主要因素.如图1所示.KS加法器在一定程度上缓解了微电子学与计算机2005年第22卷第12期LF加法器大扇出的问题KS加法器充分利用了冥等律的特点.通过限制每一个节点的输出来减小扇出.但是付出的代价就是每一级中使用了更多的横向连线.在KS加法器中.最长连线的长度与LF加法器中的一样如图3所示.为了改进LF加法器的扇出,BK加法器增加了逻辑层次深度3并行前缀加法器电路特性分析为了简化三种加法器结构的比较.假设加法器的输入是同时达到在没有考虑连线延迟和扇出影响的情况下.KS加法器和LF加法器拥有最小的加法器延迟.而BK加法器由于其逻辑层次深度多了一级.因此比起KS加法器和LF加法器而言,延迟较大.但是随着CMOS工艺的不断发展.扇出和连线对电路延迟的影响已经起着重要的作用.因此. 评判加法器延迟的大小.已经不能够仅仅只关注逻辑电路层次的多少.同时也更要考虑扇出和连线的影响.在电路中.一段连线的模型分割成为多个短线.其中每一短线可以抽象成为分布式的连线模型.如图4所示其中.逻辑输入电容C;输出电阻.;门延迟;(C和为每一个线段的电容,电阻;(CL)为连线每一个负载节点i的负载电容图4分布式连线模型因此.总延迟就是每一级逻辑的延迟与每一级线段延迟的总和,即=+.当不考虑连线延迟的时候,根据文献[8],可以将逻辑延迟模型简化为lumpedRC模型.Ⅳ=+o.7Ro(CL)(11)/=1然而.随着工艺特征尺寸的不断下降.连线所引起的延迟越来越占据总延迟中的较大比重.文献提出了一种连线延迟的估计模型.如式(12)所示: NNNN=∑∑=∑(∑(12)/=1j=l/=1j=l根据文献[8],整个连线延迟公式可以简化为:NNo.7.∑(c+∑(0.4(Cw)+o.7(CL)Ⅳ+o.7∑((+(c))(13)j=/+l其中,第一项是连线电容效应,也就是连线的lumpedRC模型.第二项是连线的电阻效应.也就是分布式RC模型.4实验结果在TSMC0.181~m1P6M工艺,0.151zm1P6M工艺,0.131zm1P7M工艺,以及90nm1P8M工艺下.针对16位宽加法器,32位宽加法器,64位宽加法器, 以及128位宽加法器的LF结构,KS结构,BK结构进行比较.如图5所示16bit32bit64bit128bitDelay(0.18n1)16bit32bit64bit128bitDelay(0.15m)16bit32bit64biL128biLDelay(0.15m)圜囵圈囵16bit32bit64bit128bitDelay(90nm1图5四种工艺和位宽下三种加法器结构性能对比从图5中可以看出.BK加法器虽然在O.181zm工艺下的延迟不是最小.但是随着工艺尺寸的不断缩小,其相对于其他结构的加法器而言,具有一定2005年第22卷第12期微电子学与计算机的优势.即使在O.181xm工艺下,64位加法器的BK结构加法器的延迟也能够满足时序要求.因此,为了满足今后设计对工艺要求不断提高.便于工艺上的转换,在实现上,宜选取BK结构作为加法器结构.5结束语随着微处理器运算速度的大幅度提高.对快速加法器的需求也越来越高.因此.人们提出了许多快速加法器结构.包括并行前缀加法器(Parallel PrefixAdder)结构由于采用了简单的标准单元以及规则的内部连接.并行前缀加法器非常适合于VLSI实现本文基于不同的CMOS工艺.针对三种不同结构的并行前缀加法器.在不同数据宽度的情况下进行性能比较.根据深亚微米下金属互连线对加法器结构的影响.挑选出了适合深亚微米工艺的加法器结构参考文献[1】KUdea,NSasaki,HSato,eta1.A64-BitCarryLookA—headUsingPassTransistorBiCMOSGate[J].IEEEJ.Sol—id—StateCircuits,1996,31:810-819.[2】KSuzuki,eta1.A500MHz32bit0.4txmCMOSRISCPro—cessor[J].IEEE,Solid-StateCircuits,1994,29(12):1464- 1476.f3】PMKogge,HSStone.AParallelAlgorithmfortheEttl—cientSolutionofaGeneralClassofRecurrenceEquationsputers,1973,22(8):786-793.f4】RELadner,MJFischer.ParallelPrefixCompu~fion[J]. JACM,1980,27(4):831-838.f5】RPBrent,HTKung.ARegularLayoutforParallel Adders[J]puters,1982,31(3):260-264.f6】JCong.ChallengesandOpportunitiesforDesignInnova—tionsinNanometerTechnologies.SRCWorkingPaper,/prg_mgmt/frontier.dgw,1997.f7】JCong,DZPan.InterconnectDelayEstimationModels forSynthesisandDesignPlanning[J]andSouth PacificDesignAutomationConf.,1999,97-100.[8】HBBakoglu.Circuit,InterconnectionsandPackagingfor VLSI[M].Addison-WesleyPublishingCompany,1990.f9】EElmore.TheTransientResponseofDampedLinearNet—workswithParticularRegardtoWidebandAmplifiers[J1. JournalofAppliedPhysics,1948,55-63.靳战鹏男,(1981~),硕士研究生.研究方向为计算机系统结构,专用微处理器设计.沈绪榜男.(1933一),博士生导师,中国科学院院士.研究方向为计算机体系结构,专用微处理器设计,超大规模集成电路设计罗晏男,(1975一),博士,讲师.研究方向为计算机系统结构,专用微处理器设计,ASIC设计.(上接第91页)型的自身结构,对其作进一步的优化,是提高FIRE—Agent求解效率的根本途径.本文进一步的工作将从上述2个方面展开.参考文献[1】eBaySite.http://www.eBay.eom.WorldWideWeb.[2】AmazonSite.http://www.amazon.eom.WorldWideWeb. [3】ZaehariaG,MacsP.TrustManagementThroughReputa—tionMechanisms.AppliedArtificialIntelligence,2000,14 (9):881-908.f4】HuynhTD,JenningsNR,ShadbohNR.FIRE:Aninte—gratedTrustandRepumtionModelforOpenMullti-agent Systems.Proc.16thEuropeanConferenceonArtificialIn—telligence,V alencia,Spain,2004:18-22.f5】ShehoryO,KrausS.CoalitionFormationAmongAu—tonomousAgents:Strategiesandcomplexity.Reactionto Cognition,LectureNotesinArtificialIntelligence,Berlin: Springer,1993,957:57-72.[6】KetchpelS.CoalitionFormationAmongAutonomousA—gents.ReactiontoCognition,LectureNotesinArtificial Intelligence,Berlin:Springer,1993,957:73～88.f7】SandholmTW,LesserVR.CoalitionAmongComputa—tionallyBoundedAgents.ArtificialIntelligence,1997,94 (1):99-137.[8】罗翊,石纯一.Agent协作求解中形成联盟的行为策略. 计算机学报,1997.20(11):961～965.『91徐晋晖,石纯一.一种基于等价的联盟演化机制.计算机研究与发展,1999,36(5):513～517.李凯男,(1977一),博士研究生,助教.研究方向为人工智能,企业建模与优化.杨善林男.(1948一),教授,博士生导师.研究方向为人工智能,信息管理与决策支持系统.刘桂庆女,(1978一),博士研究生,讲师.研究方向为供应链管理,人工智能.。

《数字信号处理的FPGA实现》读书笔记

<数字信号处理的FPGA实现>Verilog写状态机大概有这样几点要求：1、组合逻辑完成状态转移的条件判断，时序逻辑完成状态机的状态转移。

2、组合逻辑和时序逻辑分别在两个不同的always块中完成，根据状态机状态通过译码逻辑产生的与状态机无关的逻辑部分不要放在专用的状态机always块中。

3、状态编码预先定义为parameter，状态较少的状态机推荐使用one-hot方式编码，以减小译码逻辑的复杂度，提高性能。

4、建议单独使用一个模块来描述状态机。

5、状态机应有一个default状态，在上电复位的时候作为初始状态。

6、注意状态机组合逻辑中的if...else语句，不要出现latch。

7、对于复杂状态机，最好采用状态机嵌套方式完成。

其实上面很多都是按照Synopsys LEDA的coding style的要求的，状态机的写法相对固定，因此很多Design entry的工具可以自动生成状态机代码，Xilinx也有工具支持直接由状态转移图输入完成状态机的编码。

所以关键还是画好状态转移图，其他就相对简单了。

visual hdl＋ISE＋synplify Pro＋modelsim！1.设计输入1)设计的行为或结构描述。

2)典型文本输入工具有UltraEdit-32和Editplus.exe.。

3)典型图形化输入工具-Mentor的Renoir。

4)我认为UltraEdit-32最佳。

2.代码调试1)对设计输入的文件做代码调试，语法检查。

2)典型工具为Debussy。

3.前仿真1)功能仿真2)验证逻辑模型(没有使用时间延迟)。

3)典型工具有Mentor公司的ModelSim、Synopsys公司的VCS和VSS、Aldec公司的Active、Cadense公司的NC。

4)我认为做功能仿真Synopsys公司的VCS和VSS速度最快，并且调试器最好用，Mentor 公司的ModelSim对于读写文件速度最快，波形窗口比较好用。

第5章(2学时) 算术逻辑单元-英文

5.2 Parallel fast adders
N-bit ripple-carry adde adder can be produced by connecting n full adders
Carry is
transferred serially, and Fi is calculated when Ci-1 is coming.
Cn-1。Result of full adder
and carry bit are given below: Fn＝XnYnCn-1+ XnYnCn-1 + XnYnCn-1+ XnYnCn-1 Cn＝ XnYnCn-1+ XnYnCn-1
+ XnYnCn-1+ XnYnCn-1
5.2 Parallel fast adders
C3=X3Y3 +(X3+Y3)X2Y2 +(X3+Y3)(X2+Y2)X1Y1 +(X3+Y3)(X2+Y2)(X1+Y1)C0 C4=X4Y4 +(X4+Y4)X3Y3 +(X4+Y4)(X3+Y3)X2Y2 +(X4+Y4)(X3+Y3)(X2+Y2)X1Y1 +(X4+Y4)(X3+Y3)(X2+Y2)(X1+Y1)C0
Design of a fast adder
How to improve the speed of
adder?
Change the pathway of one by one carry bits
Cn＝ XnYnCn-1+ XnYnCn-1 + XnYnCn-1+ XnYnCn-1 ＝(Xn+Yn) Cn-1+ XnYn

Ripple-carry adder

专利名称：Ripple-carry adder 发明人：Karl Knauer申请号：US06/902745申请日：19860902公开号：US04839849A公开日：19890613专利内容由知识产权出版社提供摘要：An adder cell for a ripple-carry adder, suitable for use in an integrated circuit employing CMOS technology, has a gate arrangement for two input variables and a carry input signal, with outputs for sum and carry signals, in accordance with the signals presented to the inputs. The gate arrangement is arranged so that the charging of the capacitance of the carry output takes place from a supply voltage through two transistor gates, not contained in a combination gate, so that one of the transistor gates may be formed as a driving inverter separate from the time-critical carry-propogation path, and designed with significantly lower impedance than the other transistor gates. Alternatively, a single transistor gate is employed for charging the capacitance of the carry output directly form a supply voltage.申请人：SIEMENS AKTIENGESELLSCHAFT代理机构：Hill, Van Santen, Steadman & Simpson更多信息请下载全文后查看。

第4讲电路级的LP设计(绝热,摆幅,循环)

Domino逻辑原理和特点
结构特点: •预充-求值动态逻辑门加一级静态CMOS反相器构成 •提高驱动（反相器） •非互补电路，面积小 •栅电容小，速度提高
动态功耗源： •Clock网络充放电 •节点电容充放电
减摆幅Domino反相器的电路实现
VDD
共n个
• F节点电压
– 低电平为0 – 高电平不大于 Vref-VTN
• 产生Vref的电路
– 源随器 – Vref=VDD-nVTN – Vref应大于2VTN以有效驱动下一级 – 可多个门共享符号图
GND
减摆幅Domino反相器的电路实现
电容C1的作用 – M1管存在CGS和CGD，源端或漏端电压改变会直接耦合到栅端，引起 Vref 跟随改变 – C1取大于5倍CGS，有效降低耦合影响，稳定Vref
N
利用率延迟
1
50％
2
67％ 2
3
75％ 3
4
80％ 4
5
83％ 5
6
86％ 6
7
87％ 7
深入分析准绝热电荷转移LP的机理
从物理上讲，它为什么能降低动态功耗？
– 降低了阻性通路上的功耗
从数学上讲，其LP机理体现在动态功耗公式中的哪个参数上？
– 数学是物理的数学表达，因此一定会有体现 – VDD n 2 – 为什么？ P ( C )V
– 栅介质
• 采用高K栅介质，在不影响电路速度的情况下减小栅极泄漏功耗
工艺级LP设计实例
– FFT芯片的LP实现
第4讲电路级的LP技术
本讲内容
降低动态功耗
准绝热电荷转移技术
• 低功耗原理 • 实例

基于组间进位预测的快速进位加法器

基于组间进位预测的快速进位加法器丁宜栋;刘昌明;方湘艳【摘要】为加快密码系统中大数加法的运算速度,提出并实现一种基于组间进位预测的快速进位加法器.将参与加法运算的大数进行分组,每个分组采用改进的超前进位技术以减少组内进位延时,组间通过进位预测完成不同进位状态下的加法运算,通过每个组产生的进位状态判断最终结果.性能分析表明,该进位加法器实现1024位大数加法运算的速度较快.%This paper presents and realizes a rapid carry adder based on carry forecast between groups to improve the speed of the large numbers adder in some cryptography systems. The large numbers is divided into many groups, the delay of carry-chain is reduced by carry lookahead in group. The group addition operation of different carry state is finished by carry forecast between groups. The addition sun of different carry forecast state is selected as the final result based on the carry state. Performance analysis shows that the computing speed of the carry adder is faster when realizing the 1 024 bit large numbers add operation.【期刊名称】《计算机工程》【年(卷),期】2011(037)023【总页数】3页(P288-290)【关键词】进位预测;大数加法器;超前进位;分组;进位加法器【作者】丁宜栋;刘昌明;方湘艳【作者单位】海军计算技术研究所,北京100841;海军计算技术研究所,北京100841;中国船舶重工集团公司第709研究所,武汉430074【正文语种】中文【中图分类】TP3091 概述在二进制加法的实现方法中，行波进位加法器(Carry Ripple Adder, CRA)[1]的结构简单，但运算时间较长；超前进位加法器(Carry Lookahead Adder, CLA)[2]速度较快，但会导致资源增加；进位跳跃加法器(Carry Skip Adder, CSA)[3]是CRA 和CLA加法器的折中。

Verilog HDL关于加法器优化的研究

veriloghdl关于加法器优化的研究
Designing of Adder
Lecturer：Prof. Wang Mingjiang Date: Theme：Algorithm of Adder
1.Full Adder
1.Full Adder
Sum=A ^ B ^ Cin Cout=A&B + B&Cin + A&Cin defination: carry delete: D=~A & ~B carry propagate: P= A ^ B carry generate: G= A & B
4. Mulitbit carry-skip Adder
module csa_16bit( a, b, ci, s, co); input[15:0] input output output[15:0] a,b; ci; co; s;
wire[3:1] wnet; csa_4bit (a[3:0], b[3:0], ci, s[3:0], wnet[1]); csa_4bit (a[7:4], b[7:4], wnet[1], s[7:4], wnet[2]); csa_4bit (a[11:8], b[11:8], wnet[2], s[11:8], wnet[3]); csa_4bit (a[15:12], b[15:12], wnet[3], s[15:12], co); endmodule
module fulladder( a,b,cin,sum,cout); input a, b, cin; output sum, cout; assign sum = a ^ b ^ cin; assign cout = a&b | a&c | b&c ; endmodule module fulladder( a, b, cin, sum, cout ); input a, b, cin; output sum, cout; wire w1, w2, w3, w4; xor u1(w1, a, b); xor u2(sum, w1, cin); or u3(w2, a, b); and u4(w3, cin, w2); and u5(w4, a, b); or u6(cout, w3,w4); endmodule

进位选择加法器之设计

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高考英语一轮复习单词清单Unit28

1.pace n.步子；节奏2.pack n.包,捆;一群v.打包3.package n. 一包,一袋,一盒4.packet n.小包裹,袋5.paddle n.桨状物,蹼6.painful adj.使痛的,使痛苦的7.painter n.绘画者,（油）画家8.painting n.油画,水彩画9.palace n.宫,宫殿10.pale adj.苍白的,灰白的11.pan n.平底锅12.pancake n.薄煎饼13.panic adj./v.惊慌,恐慌,惶恐不安14.paperwork n.日常文书工作15.paragraph n.（文章的）段落16.parallel n.极其相似的人,纬线17.parcel n.包裹18.pardon n.原谅,宽恕,对不起19.park vt.停放（汽车）20.parrot n.鹦鹉21.part n.部分；角色；部件；零件v.分开22.participate v.参加,参与23.particular adj.特定的,个别的24.partly adv.部分地,在一定程度上25.partner n.搭档,合作者26.party n.聚会；党派27.pass vt.传,递；通过28.passage n.（文章等的）一节,一段；通道；走廊29.passenger n.乘客,旅客30.passerby n.过路人31.passive adj.被动的32.passport n.护照33.past n.过去prep.经过34.patent n.专利权,专利证书35.path n.小道,小径36.patience n.容忍；耐心37.patient n.病人38.pattern n.式样39.pause n.&vi.中止,暂停40.pay(paid,paid)v.付钱,n.工资41.P.E.体育(缩)=physicaleducation42.pea n.豌豆43.peace n.和平44.peaceful adj.和平的,安宁的45.peasant n.农民；佃农46.pedestrian n.行人47.pension n.养老金48.pepper n.胡椒粉49.per prep.每,每一50.percent n.百分之……51.percentage n.百分率52.perfect adj.完美的,极好的53.perform v.表演,履行；行动54.performance n.演出,表演55.performer n.表演者,执行者56.perfume n.香水57.period n.时期,时代58.permanent adj.永久的,永恒的59.permission n.允许,许可,同意60.permit vt.许可,允许;执照n.许可证61.personal adj.个人的,私人的62.personnel n.全体人员,职员63.personally adv.就自己而言64.persuade vt.说服,劝说65.pest n.害虫66.pet n.宠物,爱畜67.petrol n.石油68.phenomenon n.现象(pl.phenomena)69.phrase n.短语；习惯用语70.physical adj.身体的；物理的71.physician n.(有行医执照的)医生72.physicist n.物理学家73.physics n.物理（学）74.pile n.堆75.pill n.药丸,药片76.pillow n.枕头77.pilot n.飞行员78.pin n.别针v.别住,钉住79.pine n.松树80.pineapple n.菠萝81.pioneer n.先锋,开拓者82.pipe n.管子,输送管83.pity n.怜悯,同情84.place n.地方v.放置,安置,安排1.Students study at their own pace(按自己的进度)and the teaches seldom set tests.2.We should take pains to improve(努力提高)ourselves through learning and get prepared for thefuture.3.I got into a panic(陷入恐慌)when I saw smoke ing out of the kitchen.4.I begged her pardon(请求她原谅)for arriving too late.5.Eleven million students in Jiangsu took an active part in/ participated actively in(积极参与了)this program in 2021.6.Parents and coaches in particular(尤其)should act as better examples for children.7.Fill in the form and return it either in person(亲自)or by post.8.The countries have been at peace(和平共处)for more than a century.9.It was a pity (that)(真遗憾)you couldn’t e.10.You can use yoghurt in place of/ instead of(替代)cream to make this salad.。

quick start guide to vhdl - brock j. lameres说明书

Q UICK S TART G UIDE TO VHDLQ UICK S TART G UIDE TO VHDL1Brock MeresBrock MeresDepartment of Electrical&Computer EngineeringMontana State UniversityBozeman,MT,USAISBN978-3-030-04515-9ISBN978-3-030-04516-6(eBook)https:///10.1007/978-3-030-04516-6Library of Congress Control Number:2018963722#Springer Nature Switzerland AG2019This work is subject to copyright.All rights are reserved by the Publisher,whether the whole or part of the material is concerned,speciﬁcally the rights of translation,reprinting,reuse of illustrations,recitation,broadcasting,reproduction on microﬁlms or in any other physical way,and transmission or information storage and retrieval,electronic adaptation,computer software,or by similar or dissimilar methodology now known or hereafter developed.The use of general descriptive names,registered names,trademarks,service marks,etc.in this publication does not imply,even in the absence of a speciﬁc statement,that such names are exempt from the relevant protective laws and regulations and therefore free for general use.The publisher,the authors,and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication.Neither the publisher nor the authors or the editors give a warranty, express or implied,with respect to the material contained herein or for any errors or omissions that may have been made.The publisher remains neutral with regard to jurisdictional claims in published maps and institutional afﬁliations. Cover illustration:#Carloscastilla j -Binary Code PhotoThis Springer imprint is published by the registered company Springer Nature Switzerland AGThe registered company address is:Gewerbestrasse11,6330Cham,SwitzerlandPrefaceThe classical digital design approach(i.e.,manual synthesis and minimization of logic)quickly becomes impractical as systems become more complex.This is the motivation for the modern digital designﬂow,which uses hardware description languages(HDL)and computer-aided synthesis/minimi-zation to create theﬁnal circuitry.The purpose of this book is to provide a quick start guide to the VHDL language,which is one of the two most common languages used to describe logic in the modern digital designﬂow.This book is intended for anyone that has already learned the classical digital design approach and is ready to begin learning HDL-based design.This book is also suitable for practicing engineers that already know VHDL and need quick reference for syntax and examples of common circuits.This book assumes that the reader already understands digital logic(i.e.,binary numbers, combinational and sequential logic design,ﬁnite state machines,memory,and binary arithmetic basics).Since this book is designed to accommodate a designer that is new to VHDL,the language is presented in a manner that builds foundational knowledgeﬁrst before moving into more complex topics. As such,Chaps.1–5only present functionality built into the VHDL standard package.Only after a comprehensive explanation of the most commonly used packages from the IEEE library is presented in Chap.7,are examples presented that use data types from the widely adopted STD_LOGIC_1164 package.For a reader that is using the book as a reference guide,it may be more practical to pull examples from Chaps.7–12as they use the types std_logic and std_logic_vector.For a VHDL novice, understanding the history and fundamentals of the VHDL base release will help form a comprehensive understanding of the language;thus it is recommended that the early chapters are covered in the sequence they are written.Bozeman,MT,USA Brock MeresAcknowledgmentsFor Alexis.The world is a better place because you are in it.Contents1:THE MODERN DIGITAL DESIGN FLOW (1)1.1H ISTORY OF H ARDWARE D ESCRIPTION L ANGUAGES (1)1.2HDL A BSTRACTION (4)1.3T HE M ODERN D IGITAL D ESIGN F LOW (8)2:VHDL CONSTRUCTS (13)2.1D ATA T YPES (13)2.1.1Enumerated Types (13)2.1.2Range Types (14)2.1.3Physical Types (14)2.1.4Vector Types (14)2.1.5User-Deﬁned Enumerated Types (15)2.1.6Array Type (15)2.1.7Subtypes (15)2.2VHDL M ODEL C ONSTRUCTION (16)2.2.1Libraries and Packages (16)2.2.2The Entity (17)2.2.3The Architecture (17)3:MODELING CONCURRENT FUNCTIONALITY (21)3.1VHDL O PERATORS (21)3.1.1Assignment Operator (21)3.1.2Logical Operators (22)3.1.3Numerical Operators (23)3.1.4Relational Operators (23)3.1.5Shift Operators (23)3.1.6Concatenation Operator (24)3.2C ONCURRENT S IGNAL A SSIGNMENTS WITH L OGICAL O PERATORS (24)3.2.1Logical Operator Example:SOP Circuit (25)3.2.2Logical Operator Example:One-Hot Decoder (26)3.2.3Logical Operator Example:7-Segment Display Decoder (27)3.2.4Logical Operator Example:One-Hot Encoder (29)3.2.5Logical Operator Example:Multiplexer (31)3.2.6Logical Operator Example:Demultiplexer (32)3.3C ONDITIONAL S IGNAL A SSIGNMENTS (34)3.3.1Conditional Signal Assignment Example:SOP Circuit (34)3.3.2Conditional Signal Assignment Example:One-Hot Decoder (35)3.3.3Conditional Signal Assignment Example:7-Segment Display Decoder (36)3.3.4Conditional Signal Assignment Example:One-Hot Encoder (37)3.3.5Conditional Signal Assignment Example:Multiplexer (38)3.3.6Conditional Signal Assignment Example:Demultiplexer (39)x•Contents3.4S ELECTED S IGNAL A SSIGNMENTS (41)3.4.1Selected Signal Assignment Example:SOP Circuit (41)3.4.2Selected Signal Assignment Example:One-Hot Decoder (42)3.4.3Selected Signal Assignment Example:7-Segment Display Decoder (43)3.4.4Selected Signal Assignment Example:One-Hot Encoder (44)3.4.5Selected Signal Assignment Example:Multiplexer (45)3.4.6Selected Signal Assignment Example:Demultiplexer (46)3.5D ELAYED S IGNAL A SSIGNMENTS (48)3.5.1Inertial Delay (48)3.5.2Transport Delay (48)4:STRUCTURAL DESIGN AND HIERARCHY (53)4.1C OMPONENTS (53)4.1.1Component Instantiation (53)4.1.2Port Mapping (53)4.2S TRUCTURAL D ESIGN E XAMPLES:R IPPLE C ARRY A DDER (56)4.2.1Half Adders (56)4.2.2Full Adders (56)4.2.3Ripple Carry Adder(RCA) (58)4.2.4Structural Model of a Ripple Carry Adder in VHDL (59)5:MODELING SEQUENTIAL FUNCTIONALITY (65)5.1T HE P ROCESS (65)5.1.1Sensitivity Lists (65)5.1.2Wait Statements (66)5.1.3Sequential Signal Assignments (67)5.1.4Variables (68)5.2C ONDITIONAL P ROGRAMMING C ONSTRUCTS (70)5.2.1If/Then Statements (70)5.2.2Case Statements (71)5.2.3Inﬁnite Loops (73)5.2.4While Loops (75)5.2.5For Loops (75)5.3S IGNAL A TTRIBUTES (76)6:PACKAGES (81)6.1STD_LOGIC_1164 (81)6.1.1STD_LOGIC_1164Resolution Function (82)6.1.2STD_LOGIC_1164Logical Operators (83)6.1.3STD_LOGIC_1164Edge Detection Functions (83)6.1.4STD_LOGIC_1164Type Converstion Functions (84)6.2NUMERIC_STD (85)6.2.1NUMERIC_STD Arithmetic Functions (85)6.2.2NUMERIC_STD Logical Functions (87)6.2.3NUMERIC_STD Comparison Functions (87)6.2.4NUMERIC_STD Edge Detection Functions (87)Contents•xi6.2.5NUMERIC_STD Conversion Functions (88)6.2.6NUMERIC_STD Type Casting (88)6.3TEXTIO AND STD_LOGIC_TEXTIO (89)6.4O THER C OMMON P ACKAGES (92)6.4.1NUMERIC_STD_UNSIGNED (92)6.4.2NUMERIC_BIT (92)6.4.3NUMERIC_BIT_UNSIGNED (93)6.4.4MATH_REAL (93)6.4.5MATH_COMPLEX (95)6.4.6Legacy Packages(STD_LOGIC_ARITH/UNSIGNED/SIGNED) (95)7:TEST BENCHES (99)7.1T EST B ENCH O VERVIEW (99)7.2G ENERATING S TIMULUS V ECTORS U SING F OR L OOPS (101)7.3A UTOMATED C HECKING U SING R EPORT AND A SSERT S TATEMENTS (102)7.3.1Report Statement (102)7.3.2Assert Statement (103)7.4U SING E XTERNAL I/O IN T EST B ENCHES (104)7.4.1Writing to an External File from a Test Bench (104)7.4.2Writing to STD_OUTPUT from a Test Bench (107)7.4.3Reading from an External File in a Test Bench (109)7.4.4Reading Space-Delimited Data from an External File in a Test Bench (111)8:MODELING SEQUENTIAL STORAGE AND REGISTERS (117)8.1M ODELING S CALAR S TORAGE D EVICES (117)8.1.1D-Latch (117)8.1.2D-Flip-Flop (118)8.1.3D-Flip-Flop with Asynchronous Resets (118)8.1.4D-Flip-Flop with Asynchronous Reset and Preset (119)8.1.5D-Flip-Flop with Synchronous Enable (120)8.2M ODELING R EGISTERS (121)8.2.1Registers with Enables (121)8.2.2Shift Registers (122)8.2.3Registers as Agents on a Data Bus (123)9:MODELING FINITE STATE MACHINES (127)9.1T HE FSM D ESIGN P ROCESS AND A P USH-B UTTON W INDOW C ONTROLLER E XAMPLE (127)9.1.1Modeling the States with User-Deﬁned,Enumerated Data Types (128)9.1.2The State Memory Process (129)9.1.3The Next State Logic Process (129)9.1.4The Output Logic Process (130)9.1.5Explicitly Deﬁning State Codes with Subtypes (132)9.2FSM D ESIGN E XAMPLES (133)9.2.1Serial Bit Sequence Detector in VHDL (133)9.2.2Vending Machine Controller in VHDL (135)9.2.32-Bit,Binary Up/Down Counter in VHDL (137)xii•Contents10:MODELING COUNTERS (143)10.1M ODELING C OUNTERS WITH A S INGLE P ROCESS (143)10.1.1Counters in VHDL Using the Type UNSIGNED (143)10.1.2Counters in VHDL Using the Type INTEGER (144)10.1.3Counters in VHDL Using the Type STD_LOGIC_VECTOR (145)10.2C OUNTERS WITH E NABLES AND L OADS (148)10.2.1Modeling Counters with Enables (148)10.2.2Modeling Counters with Loads (149)11:MODELING MEMORY (153)11.1M EMORY A RCHITECTURE AND T ERMINOLOGY (153)11.1.1Memory Map Model (153)11.1.2Volatile vs.Nonvolatile Memory (154)11.1.3Read-Only vs.Read/Write Memory (154)11.1.4Random Access vs.Sequential Access (154)11.2M ODELING R EAD-O NLY M EMORY (155)11.3M ODELING R EAD/W RITE M EMORY (158)12:COMPUTER SYSTEM DESIGN (163)12.1C OMPUTER H ARDWARE (163)12.1.1Program Memory (164)12.1.2Data Memory (164)12.1.3Input/Output Ports (164)12.1.4Central Processing Unit (164)12.1.5A Memory-Mapped System (166)12.2C OMPUTER S OFTWARE (168)12.2.1Opcodes and Operands (169)12.2.2Addressing Modes (169)12.2.3Classes of Instructions (170)12.3C OMPUTER I MPLEMENTATION:A N8-B IT C OMPUTER E XAMPLE (177)12.3.1Top-Level Block Diagram (177)12.3.2Instruction Set Design (178)12.3.3Memory System Implementation (179)12.3.4CPU Implementation (184)APPENDIX A:LIST OF WORKED EXAMPLES (207)INDEX (211)。

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4-bit Carry Ripple Adder
Assume you want to add two operands A and B where
A= A3 A2 A1 A0
B=B3 B2 B1 B0
For example: A= 1 0 1 1 +
B= 1 1 0 1
---------------
A+B= 11 0 0 0 = C out S3 S2 S1 S0
From the example above it can be seen that we are adding 3 bits at atime sequentially until all bits are added. A full adder is a combinational circuit that performs the arithmetic sum of three input bits: augends Ai, addend Bi and carry in
C from the
in
previous adder. Its results contain the sum Si and the carry out,
C to the next stage.
out
Fig. 1 4_bit adder
So to design a 4-bit adder circuit we start by designing the 1 –bit full adder then connecting the four 1-bit full adders to get the 4-bit adder as shown in the diagram above. For the 1-bit full adder, the design begins by drawing the Truth Table for the three input and the corresponding output SUM and CARRY. The Boolean Expression describing the binary adder circuit is then deduced. The binary full adder is a three input combinational circuit which satisfies the truth table below.
Fig.2. Diagram and Truth Table of Full Adder
The Boolean equations of a full adder are given by:
S = ABC + AB’C’ + A’B’C + BA’C’
out
=(AB’+BA’)C +AB+A’B’) C’
S = A⊕B⊕C
out
C = AB + AC + BC
out
C = AB + C (A⊕B)
out
The circuit diagram is shown in Fig.3 and the simulation results is shown in Fig. 4
Fig. 3. The Gate level Diagram of Full Adder
Fig. 4 1 bit full adder simulation results
To design a 4-bit adder now we cascade 4 1-bit adders as shown in Fig. 5 Array
Fig. 5 4-bit Ripple Carry adder
As is seen from Fig. 5 and Fig. 6 the carry ripples through the 4 full adders to appear at the output, while the sums are available after 2 XOR delay.
Fig. 5 Carry Propagation
The carry propagation is shown in Fig. 5 as a block and as a path through the circuit in Fig. 6
Fig. 6 carry propagation through the circuit
Cin。