• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.10
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• pp.72-81
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• 2011

In this paper, we proposed and designed a novel floating point converter which supports single and double precisions of IEEE754 standard. The proposed convertor supports conversions between floating point number single/double precision and signed fixed point number(32bits/64bits) as well as conversions between signed integer(32bits/64bits) and floating point number single/double precision and conversions between floating point number single and double precisions. We defined a new internal format to convert various input types into one type so that overflow checking could be conducted easily according to range of output types. The internal format is similar to the extended format of floating point double precision defined in IEEE754 2008 standard. This standard specifies that minimum exponent bit-width of the extended format of floating point double precision is 15bits, but 11bits are enough to implement the proposed converting unit. Also, we optimized rounding stage of the convertor unit so that we could make it possible to operate rounding and represent correct negative numbers using an incrementer instead an adder. We designed single cycle data path and 5 cycles data path. After describing the HDL model for two data paths of the convertor, we synthesized them with TSMC 180nm technology library using Synopsys design compiler. Cell area of synthesis result occupies 12,886 gates(2 input NAND gate), and maximum operating frequency is 411MHz.

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.353-356
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• 2000

In this paper, a high-performance and small-area floating-point divider, which is suitable for embedded processors and supports all rounding modes defined by IEEE 754 standard, is designed using the series expansion algorithm. This divider shares and fully utilizes the two MAC units for quadratical convergence to the correct quotient. The area increase of two MAC units due to the division is minimized in this design, so that it can be suitable for embedded processors. The tested HDL codes are synthesized and optimized with 0.35$\mu\textrm{m}$ CMOS standard celt libraries. The results show that the latency of the synthesized divider is 17.43 ㎱ in worst condition. But, the divider calculates the correct rounded quotient through only 6 cycles.

• Proceedings of the KIEE Conference
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• 1999.11c
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• pp.788-790
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• 1999

A software implementation of floating-point addition and multiplication is presented. For this, the ANSI/IEEE standard for binary floating-point arithmetic is reviewed briefly. The architecture and behavior of the $Intel^{(R)}\;80{\times}87$ FPU is fully studied and basic algorithms for floating-point addition and multiplication are used for the implementation. Some examples and their verifications are also presented.

• Proceedings of the KIEE Conference
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• 1999.11c
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• pp.778-780
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• 1999

Arithmetic unit speed depends strongly on the algorithms employed to realize the basic arithmetic operations.(add, subtract multiply, and divide) and on the logic design. Recent advances in VLSI have increased the feasibility of hardware implementation of floating point arithmetic units and microprocessors require a powerful floating-point processing unit as a standard option. This paper describes the design of floating-point multiplier for IEEE 754-1985 Single-Precision operation. Booth encoding algorithm method to reduce partial products and a Wallace tree of 4-2 CSA is adopted in fraction multiplication part to generate the $32{\times}32$ single-precision product. New scheme of rounding and sticky-bit generation is adopted to reduce area and timing. Also there is a true sign generator in this design. This multiplier have been implemented in a ALTERA FLEX EPF10K70RC240-4.

• Proceedings of the KIEE Conference
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• 2001.11c
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• pp.165-168
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• 2001

This paper presents a design of a divide unit supporting IEEE-754 floating point standard single-precision with 32-bit word length. Its functions have been verified with ALTERA MAX PLUS II tool. For a high-speed division operation, the radix-4 non-restoring algorithm has been applied and CLA(carry-look -ahead) adders has been used in order to improve the area efficiency and the speed of performance for the fraction division part. The prevention of the speed decrement of operations due to clocking has been achieved by taking advantage of combinational logic. A quotient select block which is very complicated and significant in the high-radix part was designed by using P-D plot in order to select the fast and accurate quotient. Also, we designed all division steps with Gate-level which visualize the operations and delay time.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.3
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• pp.517-524
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• 2001

This paper describes a design of radix-2 SRT divider unit, which supports IEEE-754 floating-point standard, using redundant binary number system (RBNS). With the RBNS, the partial quotient decision logic can operate about 20-% faster, as well as can be implemented with a simple hardware when compared to the conventional methods based on two's complement arithmetic. By using a new redundant binary adder proposed in this paper, the mantissa divider is efficiently implemented, thus resulting in about 20% smaller area than other works. The divider unit supports double precision format, five exceptions and four rounding modes. It was verified with Verilog HDL and Verilog-XL.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.7
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• pp.66-73
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• 2002

As floating-point operations become widely used in various applications such as computer graphics and high-definition DSP, the needs for fast division become increased. However, conventional floating-point dividers occupy a large hardware area, and bring bottle-becks to the entire floating-point operations. In this paper, a high-performance and small-area floating-point divider, which is suitable for embedded processors, is designed using he series expansion algorithm. The algorithm is selected to utilize two MAC(Multiply-ACcumulate) units for quadratic convergence to the correct quotient. The two MAC units for SIMD-DSP features are shared and the additional area for the division only is very small. The proposed divider supports all rounding modes defined by IEEE 754 standard, and error estimations are performed for appropriate precision.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.39 no.2
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• pp.1-5
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• 2002

Floating point unit system follows IEEE 754 Standard. In this paper, we used 1's complement system instead of 2's complement to practice the arithmetic. By converting we enable this system to compute simply and fast. To improve the speed of newly design adder, we used a transformation Carry selector adder of 53 bits. In paper, a design of floating point unit high efficiency micro processor system about for high speed. 

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.10
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• pp.82-90
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• 2011

Because of the development of Smart phone devices, the demands of high performance FPU(Floating-point Unit) becomes increasing. Therefore, we propose the high-speed single-/double-precision FPU design that includes an elementary add/sub unit and improved multiplier and compare and convert units. The most commonly used add/sub unit is optimized by the parallel rounding unit. The matrix operation is used in complex calculation something like a graphic calculation. We designed the Multiply-Add Fused(MAF) instead of multiplier to calculate the matrix more quickly. The branch instruction that is decided by the compare operation is very frequently used in various programs. We bypassed the result of the compare operation before all the pipeline processes ended to decrease the total execution time. And we included additional convert operations that are added in IEEE754-2008 standard. To verify our RTL designs, we chose four hundred thousand test vectors by weighted random method and simulated each unit. The FPU that was synthesized by Samsung's 45-nm low-power process satisfied the 600-MHz operation frequency. And we confirm a reduction in area by comparing the improved FPU with the existing FPU.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.232-235
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• 1999

In this paper, we present a coprocessor that can operate with ARM microprocessors. The coprocessor supports IEEE 754 standard single- and double-precision binary floating point arithmetic operations. The design objective is to achieve minimum-area, low-power and acceleration of processing power of ARM microprocessors. The instruction set is compatible with ARM7500FE. The coprocessor is written in verilog HDL and synthesized by the SYNOPSYS Design Compiler. The gate count is 38,115 and critical path delay is 9.52ns.