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Proceeding Paper

Analysis and Synthesis of Single-Bit Adders for Multi-Bit Adders with Sequential Transfers †

1
International University of Information Technology, Almaty 050013, Kazakhstan
2
School of Information Technology and Engineering, Kazakh-British Technical University, Almaty 050000, Kazakhstan
3
Kazakh National University named after Al-Farabi, Almaty 050040, Kazakhstan
4
Academy of Logistics and Transport, Almaty 050012, Kazakhstan
5
Department of Telecommunications, University of Ruse, 7004 Ruse, Bulgaria
*
Author to whom correspondence should be addressed.
Presented at the International Conference on Electronics, Engineering Physics and Earth Science (EEPES’24), Kavala, Greece, 19–21 June 2024.
Eng. Proc. 2024, 70(1), 6; https://doi.org/10.3390/engproc2024070006
Published: 24 July 2024

Abstract

:
This paper provides an analysis of existing single-digit binary adders from the point of view of their implementation on fans built based on metal-oxide-semiconductor field-effect transistor—MOSFETs. The synthesis of a single-digit adder with a conditional sum is carried out. The considered adders are compared in terms of speed and hardware complexity (by the number of MOSFETs). Adders perform arithmetic operations on numbers. In combination with other logical operations, adders are the core of the circuits of arithmetic logic devices that implement several different operations; they are an integral part of different processors. The most important parameters of adders are their hardware complexity and performance; therefore, many options for single-bit and multi-bit connectors with serial, parallel and combined transmissions have been developed. In the final part, a scheme of a multi-bit adder with consecutive transfers on adders with a conditional sum is given. An example of performing addition operations is given.

1. Introduction

Adders perform arithmetic addition and subtraction of numbers. Together with other logical operations, adders are the core of the circuits of arithmetic logic devices that implement a number of various operations (multiplication, division, etc.), which are an indispensable part of various processors.
Important parameters of adders are their hardware complexity and performance; therefore, many variants of single-bit and multi-bit adders with serial, parallel and combined transfers have been developed [1].
The listed adders are synthesized based on the truth table. The analytical expressions of the sum (Si) and transfer functions Ci have the form:
S i = a i ¯ b i ¯ C i 1 a i ¯ b i C i 1 ¯ a i b i ¯ C i 1 ¯ a i b i C i 1 ; C i = a i b i a i   C i 1   b i   C i 1 ,
where a i ¯ and b i ¯ are the i-th digits of the numbers A and B; C i 1 —transfer from the junior category.
The formula can be reproduced on various sets of logic elements, such as AND-NOT, OR-NOT, “exclusive OR”, etc. At the same time, the hardware’s complexity and performance may be different.

2. Materials and Methods

The analysis of single-digit adders on elements is discussed below:
  • two-stage logic AND-OR-NOT [1];
  • two “exclusive OR” valves and OR-NOT and AND-NOT circuits [2];
  • three-way valve “exclusive OR” and circuits AND-NOT;
  • on valves “exclusive OR” and multiplexers, an adder with a conditional sum (conditional-sum addition_CSA) is implemented. Before determining the hardware complexity (the number of MOSFETs) and performance (the number of logic elements on which the signal is delayed), the circuits of the analyzed adders are depicted as logic gates on the MOSFET. Consider the analysis of an adder built on the basis of the two-stage logic AND-OR-NOT [1,3,4,5].
The circuit of such an adder is shown in Figure 1, and Figure 2 shows the circuit of this adder on the logic circuits of a MOSFET [6,7,8].
The analytical formula of the analyzed adder has the form:
C i   = ( a i b i a i C i 1 b i C i 1 ) ; S i = C i 1 ¯ ( a i b i C i 1 ) a i b i C i 1 .
Figure 1 shows the functional diagram of the adder constructed according to Formula (2).
Figure 2 shows its logic circuit on a MOSFET.
Figure 2 shows that the adder consists of six AND-NOT circuits with two inputs each. To implement them, 6 × 4 = 24 transistors will be required. It has nine circuits of NOT (2 × 9 = 18) transistors and a gate AND-NOT for 3 inputs (6 transistors), a gate OR-NOT for 3 inputs (6 transistors) and a gate OR-NOT for 4 inputs (8 transistors). In total, 62 MOSFETs will be required to implement the adder.
The time of formation of the transfer tci = 4 τle.
The time of formation of the sum Si = 7 τle.
The second single-digit adder [2,3,9], which is subject to analysis, refers to the following formula:
S i = C i 1 a i b ; i C i = a i b i ¯   a i c i 1 ¯   b i c i 1 ¯ .
The functional scheme of the Ci transfer is shown in Figure 3, which consists of three two-input and one three-input AND-NOT circuit. To implement them, we will need (4 × 3) + 6 = 18 transistors. The time of transfer formation tci = 2 τle.
The Si value in Formula (3) is calculated by adding modulo 2 (Si1 = ai bi), then Si = Si1  Ci−1 is calculated (the first option). Figure 4 shows a functional scheme for calculating Si based on two addition schemes modulo two.
S i 1 = a i ¯ b i a i b i ¯ ; S i =   S i 1 ¯ C i 1 S i 1 C i 1 ¯ .
Figure 4 shows that the implementation of Si will require four inverters and six two-input AND-NOT circuits, which will require (4 × 2) + (6 × 4) = 30 transistors.
In total, to build an adder on two circuits modulo 2, we will need (18 + 32) = 50 transistors. The second adder can be built on the basis of an adder modulo two of three variables. In our case, ai, bi and Ci−1 come in as input variables. Then, the truth table for Si has the form as shown in Table 1.
From this table we have:
S i   = C i 1 ¯ a i ¯ b i C i 1 ¯ a i b i ¯ C i 1 a i ¯ b i ¯ C i 1 a i b i .
To calculate Si, the Formula (5) is transformed as follows:
S i   = C i 1 ¯ a ¯ b i C i 1 ¯ a i b i ¯ i C i 1 a i ¯ b i ¯ C i 1 a i b i ̿ = C i 1 ¯ a i ¯ b i ¯ ( C i 1 ¯ a i b i ¯ ) ¯ ( C i 1 a i ¯ b i ¯ ) ¯ ( C i 1 a i b i ) ¯ ¯ .
The functional scheme for the sum of Si constructed according to the Formula (6) is shown in Figure 5.
According to Figure 5, it is not difficult to calculate that 38 MOSFETs will be required for the implementation of the Si adder.
According to Figure 3, to calculate Ci, 18 transistors will be required for a total of 56 transistors. For the formation of Si, a delay on 3 logical elements will be required, i.e., tsi = 3 τle.
Recently, the construction of so-called conditional sum adders (conditional-sum addition_ CSA) has been vigorously discussed [10,11,12,13,14].
The adder with a conditional sum is also built according to the truth table. Table 2 shows a modified table of the truth of the adder.
From the first part of Table 2, where Ci−1 = 0, we have
S i 0 = a i ¯ b i a i b i ¯ ;
C i 0 = a i b i .
From the second part of Table 2, where Ci−1 = 0, we have
S i 1 = a i ¯ b i ¯ a i b i .
C i 1 = a i ¯ b i a i b i ¯ a i b i = a i b i
From this table it is also easy to see that
Si = S i 0 ¯
To construct the sum of Si0 on the fans AND-NOT, OR-NOT and NOT, Formula (7) must be reduced to the form:
S i 0 = ( a i b i ) a i b i ¯ = ( a i b i ) a i b i ¯ ¯ ¯ = a i b i ¯ + ( a i b i ) ¯ ¯ ¯
According to the Formulas (8), (10), (11) and (12) it is possible to put the functional sum of the adder on the conditional sum. At the same time, the functional circuit must be supplemented with multiplexers that are controlled by transferring from the lower digit to a selection of one of Ci0 and Ci1 and one of Si0 and Si1, forming a transfer to the next digit Ci and the value of the sum Si.
Taking into account the above, the functional scheme of the adder has the form as the scheme shown in Figure 6.
The adder consists of two circuits, OR-NOT1 and AND-NOT2, three inverters, INV1, INV2 and INV3, and a MUX1 and MUX2 multiplexer. At the inputs of the circuits OR-NOT1 and AND-NOT2, are the i-th digits ai and bi of the numbers A and B. At the output of the valve AND-NOT2, the sum of Si0 is formed, which is fed to the input “0” of the MUX1 multiplexer and to the input of the inverter INV2, and at its output, the sum of Si is formed, which enters the input “1” MUX1 multiplexer. From the output of the inverter INV1, transfer Ci0 = a i b i ¯ ¯ = a i b i enters the input “0” of the MUX2 multiplexer. From the output of the inverter INV3 transfer:
C i 1 = a i b i ¯ ¯ = a i b i
It is fed to the input “1” of the MUX2 multiplexer. The control inputs of the multiplexers are transferred from the lower-order Ci−1.
The adder works as follows. After the bits ai and bi are fed to the inputs of the gates OR-NOT1 and AND-NOT1, the value of Si0 is formed at the output of the circuit OR-NOT2, and the value of the sum Si1 is formed at the output of the inverter INV2. At the same time, the transfer value Ci0 is formed at the output of the inverter INV1 and the transfer value Ci1 is formed at the output of the inverter INV3.
After feeding the transfers Ci0 and Ci1 and the sums Si0 and Si1 at the input of the corresponding multiplexers by transferring Ci−1, which is fed to the control inputs of the multiplexers simultaneously, the value of the sum Si is formed at the output of the MUX1 multiplexer and at the same time, the transfer C1 is formed at the output of the MUX2 multiplexer, which is fed to the inputs of the multiplexers of the next highest digit.

3. Result and Discussion

Figure 7 shows the functional diagram of the MUX1 multiplexer on the MOSFET and the MUX1 operation Table 3.
Figure 8 shows the functional diagram of the MUX2 multiplexer and its operation table (Figure 8).
To build a CSA adder, an AND-NOT gate is required for two inputs (4 transistors), two OR-NOT gates for 2 inputs (2 × 4 = 8 transistors), 3 inverters INV1/INV3 (3 × 2 = 6 transistors) and 2 multiplexers (2 × 6 = 12 transistors). Everything will be required for a total of 30 transistors (4 + 8 + 6 + 12 = 30 transistors). The Si formation time is 4 τle and the delay time on multiplexers is 2 τle.
Table 4 shows an example of a truth table for MUX2, which is shown in Figure 8.
The order of operation of the bit adder with a conditional sum is given in Table 5.
From Figure 8, it is not difficult to calculate the number of transistors. To form the transfers of Ci0 and Ci1 and the sums of Si0 and Si1, 18 transistors are required. To build two multiplexers, 12 transistors are required.
Total Vtr = 18 + 12 = 30 transistors.
The maximum delay time for the formation of Si0 and Si1 = 4τle, the delay time on parallel functioning multiplexers is −2τl7. A summary table of the main parameters for the considered adders is given in Table 6.
Table 6 shows that for the construction of a single-digit adder, the minimum number of transistors has an adder with a conditional sum. The same adder has a minimal delay in the formation of inter-bit transfers. An example of adding numbers to four-digit (N = 4) adders with a conditional sum is shown in Figure 9.
Let A   =   a 3 a 2 a 1   =   1 1 0 0 2        +     B   =   b 3 b 2 b 1    0 1 0 1 2     C 0   =   1          1 2 ¯        1 0 0 1 0 2 .
Using Table 3, let us consider the operation of adding numbers A and B:
  a0 = 0   b0 = 1   C0 = 1.
According to the line 7  S00 = 1 S01 = 0 and C00 = 0 C01 = 1.
At the same time S0 = 0 and C1 = 1
1.
a0 = 0   b0 = 1   C0 = 1
According to the line 7  S00 = 1 S01 = 0 and C00 = 0 C01 = 1
At the same time S0 = 0 and C1 = 1
2.
a1 = 0   b1 = 1   C1 = 1
According to the line 5  S10 = 0 S11 = 1 and C10 = 0 C01 = 0
At the same time S1 = 1 and C2 = 0
3.
a2 = 1   b2 = 1   C2 = 0
According to the line 4  S20 = 0 S21 = 1 and C2p = 1 C21 = 1
At the same time S2 = 0 and C2 = 1
4.
a3 = 1   b3 = 0   C2 = 1
According to the line 7  S30 = 1 S31 = 0 and C30 = 0 C31 = 1
At the same time S3 = 0 and C4 = S5 = 1
  SA+B = 100102 = 1810
For N bit adders, Tsm = Tsm = nτMUX + 4τl.7.
By τMUX = 2τl7
Tsm = (2n + 4)τl7.

4. Conclusions

This paper analyzes adders built on the basis of the two-stage logic AND-OR-NOT and on the two- and three-input “exclusive OR” circuits, synthesizing a conditional sum adder. The main parameters (the number of MOSFETs and the speed of adders) are determined. It is shown that from the point of view of the number of transistors and the time of formation of inter-bit transfers, the conditional sum adder is advantageous. The efficiency of the adder is shown by an example. The final part shows a functional diagram of a four-digit adder with consecutive transfers.

Author Contributions

Conceptualization, S.T., A.M. (Assel Mukasheva), G.S., T.I., K.I. and T.I.; methodology, S.T., A.M. (Assel Mukasheva) and K.I.; software, K.I. and A.M. (Assel Mukasheva); validation, A.M. (Adil Mukhamedgali), G.S., T.I. and K.I.; formal analysis, S.T. and T.I.; investigation, S.T., A.M. (Adil Mukhamedgali), G.S. and T.I.; resources, S.T.; data curation, K.I. and A.M. (Adil Mukhamedgali); writing—original draft preparation, T.I. and G.S.; writing—review and editing, K.I., A.M. (Adil Mukhamedgali), G.S. and T.I.; visualization, K.I. and A.M. (Adil Mukhamedgali); supervision, T.I.; project administration, A.M. (Adil Mukhamedgali). All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The data are not publicly available.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Ugryumov, E.P. Digital Circuitry: Textbook. Handbook for Universities, 2nd ed.; BHV-Petersburg: St. Petersburg, Russia, 2005. [Google Scholar]
  2. Lekhin, S.N. L52 Computer Circuitry; BHV-Petersburg: St. Petersburg, Russia, 2010. [Google Scholar]
  3. Ercegovac, M.D.; Lang, T. Digital Arithmetic; Morgan Kaufmann Publishers: San Francisco, CA, USA, 2004. [Google Scholar]
  4. Kartsev, M.A. Arithmetic of Digital Machines; Publishing House “SCIENCE”: Moscow, Russia, 1969; p. 676. [Google Scholar]
  5. De Dinechin, F.; Ercegovac, M.D.; Muller, J.-M.; Revol, N. Digital Arithmetic; Wiley Encyclopedia of Computer Science and Engineering: Hoboken, NJ, USA, 2009. [Google Scholar] [CrossRef]
  6. David, M.H.; Sarah, L.H. Digital Circuitry and Computer Architecture, 2nd ed.; Kaufman Morgan: New York, NY, USA, 2012. [Google Scholar]
  7. Huang, Y.M.; Kuo, J.B. A high-speed conditional carry select (CCS) adder circuit with a successively incremented carry number block (SICNB) structure for low-voltage VLSI implementation. IEEE Trans. Circuit Syst. II Analog. Digit. Signal Process. 2000, 47, 1074–1079. [Google Scholar] [CrossRef]
  8. Wang, Y.; Pai, C.; Song, X. The design of hybrid carry-lookahead/carry-select adders. IEEE Trans. Circuit Syst. II Analog. Digit. Signal Process. 2002, 49, 16–24. [Google Scholar] [CrossRef]
  9. Patterson, D.; Hennessy, J.J. Computer Architecture and Design of Computer Systems, 4th ed.; Peter: St. Petersburg, Russia, 2012. [Google Scholar]
  10. Sklansky, J. Conditional-Sum Addition Logic. IRE Trans. Electron. Comput. 1960, EC-9, 226–231. [Google Scholar] [CrossRef]
  11. Lo, J.-J. Fast binary adder with conditional transfer generation. IEEE Trans. A Comput. 1997, 46, 248–253. [Google Scholar]
  12. Niyazova, K.; Mukasheva, A.; Balbayev, G.; Iliev, T.; Mirambayeva, N.; Uzakbayev, M. Ant Colony Optimization Algorithm for Feature Selection in Suspicious Transaction Detection System. Eng. Proc. 2024, 60, 18. [Google Scholar] [CrossRef]
  13. Cheng, K.-X.; Chen, S.-W. Improved the 32-bit conditional sum Adder for low-power high-speed applications. J. Inf. Sci. Eng. 2006, 22, 975–989. [Google Scholar]
  14. Kossakov, M.; Mukasheva, A.; Balbayev, G.; Seidazimov, S.; Mukammejanova, D.; Sydybayeva, M. Quantitative Comparison of Machine Learning Clustering Methods for Tuberculosis Data Analysis. Eng. Proc. 2024, 60, 20. [Google Scholar] [CrossRef]
Figure 1. Functional diagram of the adder.
Figure 1. Functional diagram of the adder.
Engproc 70 00006 g001
Figure 2. Logic circuit of the adder on a MOSFET.
Figure 2. Logic circuit of the adder on a MOSFET.
Engproc 70 00006 g002
Figure 3. Functional scheme of Ci transfer.
Figure 3. Functional scheme of Ci transfer.
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Figure 4. Functional diagram of the Si calculator based on two addition schemes modulo two.
Figure 4. Functional diagram of the Si calculator based on two addition schemes modulo two.
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Figure 5. Functional diagram of the Si calculator based on two addition schemes modulo two.
Figure 5. Functional diagram of the Si calculator based on two addition schemes modulo two.
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Figure 6. Functional diagram of the conditional sum adder.
Figure 6. Functional diagram of the conditional sum adder.
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Figure 7. Functional diagram of MUX1 multiplexer on the MOSFET.
Figure 7. Functional diagram of MUX1 multiplexer on the MOSFET.
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Figure 8. MUX2 multiplexer function diagram.
Figure 8. MUX2 multiplexer function diagram.
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Figure 9. Functional diagram of a multi–bit adder based on a single-bit conditional sum adder.
Figure 9. Functional diagram of a multi–bit adder based on a single-bit conditional sum adder.
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Table 1. The truth table for the sum of Si.
Table 1. The truth table for the sum of Si.
Ci−1aibiSi
0000
0011
0101
0110
1001
1010
1100
1111
Table 2. Modified adder truth table.
Table 2. Modified adder truth table.
Ci−1aibiSi0Si1Ci0Ci1
0000-00
0101-0-
0011-0-
0110-1-
100-1-0
110-0-1
101-0-1
111-1-1
Table 3. Modified adder truth table.
Table 3. Modified adder truth table.
Ci−1Si0Si0Si
0010
0101
1011
1101
Table 4. MUX2 multiplexer truth table.
Table 4. MUX2 multiplexer truth table.
Ci−1aibiCi0Ci1Ci
000000
001010
010010
011111
100000
101011
110011
111111
Table 5. The order of operation of the adder with a conditional sum.
Table 5. The order of operation of the adder with a conditional sum.
Ci−1aibiSi0Si1Ci0Ci1SiCi
1000010000
2001100110
3010100110
4011011101
5100010010
6101100101
7110100101
8111011111
Table 6. The order.
Table 6. The order.
AddersNumber of Transistors (N)Time of Transfer FormationMultiplexer
Delay
Time of Sum Formation on n-bit Adder
Adder on two-stage logic (CM-1)624 τle-7 nτle
Adder on two schemes “Excluding OR” (CM-3)502 τle-6 nτle
Adder on a three-input circuit “Excluding OR” (CM-3)562 τle-3 nτle
Conditional sum adder (CSA)
(CM-4)
302 τle2 τle4 τle + nτMUX
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MDPI and ACS Style

Tynymbayev, S.; Mukasheva, A.; Ibragimov, K.; Mukhamedgali, A.; Sergazin, G.; Iliev, T. Analysis and Synthesis of Single-Bit Adders for Multi-Bit Adders with Sequential Transfers. Eng. Proc. 2024, 70, 6. https://doi.org/10.3390/engproc2024070006

AMA Style

Tynymbayev S, Mukasheva A, Ibragimov K, Mukhamedgali A, Sergazin G, Iliev T. Analysis and Synthesis of Single-Bit Adders for Multi-Bit Adders with Sequential Transfers. Engineering Proceedings. 2024; 70(1):6. https://doi.org/10.3390/engproc2024070006

Chicago/Turabian Style

Tynymbayev, Sakhybay, Assel Mukasheva, Kuanyshbek Ibragimov, Adil Mukhamedgali, Gani Sergazin, and Teodor Iliev. 2024. "Analysis and Synthesis of Single-Bit Adders for Multi-Bit Adders with Sequential Transfers" Engineering Proceedings 70, no. 1: 6. https://doi.org/10.3390/engproc2024070006

APA Style

Tynymbayev, S., Mukasheva, A., Ibragimov, K., Mukhamedgali, A., Sergazin, G., & Iliev, T. (2024). Analysis and Synthesis of Single-Bit Adders for Multi-Bit Adders with Sequential Transfers. Engineering Proceedings, 70(1), 6. https://doi.org/10.3390/engproc2024070006

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