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Floating Point Multiplier Performing IEEE Rounding and Addition in Parallel
Han,Tack-Don,Park,Woo-Chan THE RESEARCH INSTITUTE OF ASIC DESIGN YONSEI UNIVE 1995 Journal of the Research Institute of ASIC Design Vol.2 No.1
Because the rounding stage of the conventional floating-point multiplier needs a high speed adder, it occupies much time and a large amount of chip area. Furthermore, it needs additional time and hardware either to process renormalization with occurs in an overflow due to rounding or to process rounding prior to normalization. This paper presents a floating-point multiplier performing addition and IEEE rounding in parallel. stage. The presented floating point multiplier needs neither the time nor a high speed adder for rounding. In addition, renormalization doesn't occur since rounding is performed prior to normalization.
면적면에서 효율적인 부동소수점 제산 및 제곱근 연산부의 설계
한탁돈(Tack-Don Han),이중언(Joong-Eon Lee),권오영(Oh-Young Kwon) 한국정보과학회 1993 정보과학회논문지 Vol.20 No.7
본 논문에서는 병렬승산기를 이용한 부동소수점 제산 및 제곱근 연산부를 설계하였다. 설계에 사용된 기본 알고리즘은 연속곱 정규화 방식(Continued-Product Normalization Method)이다. 연속곱 정규화 방식은 젯수를 1로 만드는 일련의 수를 젯수와 피젯수에 곱하여 피젯수/젯수 형태가 몫/1의 형태로 변형시켜 원하는 결과를 얻는 방법이다. 이 방식은 x×(2-x)나 x×(3-x)/2를 계산해 나가야 한다. 그러나 (2-x)나 (3-x)/2를 계산하는데는 많은 부담이 따른다. 우리는 수정형 Booth알고리즘을 이용하여 (2-x)와 (3-x)/2을 구하는 새로운 알고리즘을 제안하였다. 이 제안된 알고리즘을 연속곱 정규화 방식에 적용하여 이 방식에 내재된 병렬성을 최대한 이용할 수 있었고, 파이프라인 기법을 효과적으로 적용하여 연산시간을 단축할 수 있었다. 그리고, (2-x)와 (3-x)/2를 위해 필요했던 한개의 레지스터와 한개의 캐리 전송 가산기가 필요없게 되므로 면적에서도 이득을 얻을 수 있었다. 설계된 연산부는 소수점 아래 7-비트까지 정확한 값을 가지는 seed 발생기를 사용하면 2배수 정확도 제산에는 8클럭 싸이클이 사용되고 제곱근 연산에는 13클럭 싸이클이 사용됨을 시뮬레이션을 통해 확인하였다. In this paper we have proposed an algorithm for a high performance floating point division and square root unit that adopts the use of a parallel multiplier. The basic algorithm used in the design is the continued-product normalization method. In the continued-product normalization method, an arbitrary number is constantly multiplied to the divisor and dividend and dividend/divisor will end up with quotient/1 and the desired result is attained. However this method requires computation of x×(2-x) and x×(3-x)/2 and this is quite an overhead. Therefore we proposed an new algorithm to compute (2-x) and (3-x)/2 by using modified Booth algorithm. When applied to the continued-product normalization method, this algorithm can maximize the inherent parallelism of continued-product normalization method, and reduce computation time by effectively applying the pipelining technique, and also achieve area efficient design by eliminating one register and one carry propagate adder which was needed for computing (2-x) and (3-x)/2. When designed unit was used with the seed generator which has the accuracy of 2^(-7), division can be executed in eight cycles and the square root operation in 13 cycles.
김경탁,김성수,최희돈,홍희도,이영택 한국식품영양학회 1996 韓國食品營養學會誌 Vol.9 No.3
일반 순간가열살균법으로 과채혼합주스를 제조한 후 저장중 성분변화를 조사하여 과채혼합주스의 저장 유통중 영양학적 의의를 밝히려 하였다. 과채혼합주스는 95℃에서 30, 70, 100초 처리하여 살균하였다. 과채혼합주스의 저장중 비타민 C 함량, 색깔변화, 총카로티노이드 함량, 총균수 및 관능검사를 실시한 결과는 다음과 같다. 과채혼합주스의 저장중 비타민 C 함량은 7일 저장시 급격히 감소하였고 7일 이상에서는 살균시간에 관계없이 시료간에 유의적 차이가 없었다(P<0.05). 색깔은 살균시간과 저장기간이 길어질수록 100, 70, 30초 처리구 순으로 변화가 심하였다. 총카로티노이드 함량은 살균시간에 큰 영향을 받지 않았으나 저장기간에 따라 약간씩 감소하였다. 총균수는 살균전 초기값이 1.1 × 10 exp (1) cfu/ml 이었으나 95℃에서 30, 70, 100초 처리했을 때 모두 음성으로, 28일 저장기간동안 균이 검출되지 않았다. 과채혼합주스의 저장중 색, 향미, 맛 및 종합적 기호도는 살균시간과 저장기간이 경과할수록 약간씩 낮아졌고, 100초 처리했을 경우 색의 변화가 가장 심하였다. The purpose of this study was to elucidate the nutritional significance of the fruit-vegetable mixed juice during storage and distribution by examining the chemical composition of the mixed juice for storage. The fruit-vegetable mixed juices were sterilized at 95℃ for 30, 70, 100 seconds and the results of the changes in vitamin C contents, colors, total carotenoid contents, total aerobic counts and sensory evaluation of the mixed juice were as follows : Vitamin C contents were drastically decreased at 7 day's storage and were not significantly different between the mixed juices at p<0.05 level after 7 day's storage. The longer the sterilization time and storage period of the mixed juice was the higher changes in color was. The color changes in the sterilized samples were higher in order of 100, 70 and 30 seconds. Total carotenoid contents were slightly decreased according to storage period but were not affected by sterilization time. Total aerobic counts were 1.0 × 10 exp (1) cfu/ml before sterilization, but it was negative after sterilization at 95℃ regardless of sterilization time. Sensory qualities such as color, flavor, taste and total acceptability of the mixed juice tended to be decreased by the increased storage period and sterilization time. Especially, the sterilized sample for 100 seconds showed lots of changes in color.
Floating Point Adder/Subtractor Performing IEEE Rounding and Addition/Subtraction in Parallel
Park,Woo-Chan,Han,Tack-Don,Kwon,Oh-Young,Lee,Shi-Wha THE RESEARCH INSTITUTE OF ASIC DESIGN YONSEI UNIVE 1995 Journal of the Research Institute of ASIC Design Vol.2 No.1
The process of the conventional floating-point addition/subtraction operation consists of alignment, addition/subtraction, normalization and rounding stages. Because the rounding stage needs a high speed adder, it occupies much time and a large amount of chip area. Furthermore, it needs additional time and hardware for renormalization which occurs in an overflow due to rounding. This paper presents a floating-point adder/subtractor performing addition/subtraction and IEEE rounding in parallel by using the characteristics of addition/subtraction and a Carry Select Adder used in the addition/subtraction stage. The floating point adder/subtractor presented does not need additional time nor a high speed adder for rounding. In addition, renormalization does not occur since rounding is performed prior to normalization.