Random Numbers part 7

psdes(&lword,&irword); itemp=jflone | (jflmsk & irword); ++(*idum); return (*(float *)&itemp); } “Pseudo-DES” encode the words. Mask to a floating number between 1 and 2. Subtraction moves range to 0. to 1. | 304 Chapter 7. Random Numbers psdes lword irword itemp jflone jflmsk irword idum return float itemp Pseudo-DES encode the words. Mask to a floating number between 1 and 2. Subtraction moves range to 0. to 1. The accompanying table gives data for verifying that ran4 and psdes work correctly on your machine. We do not advise the use of ran4 unless you are able to reproduce the hex values shown. Typically ran4 is about 4 times slower than ran0 or about 3 times slower than rani. Values for Verifying the Implementation of psdes idum before psdes call after psdes call hex ran4 idum lword irword lword irword VAX PC -1 1 1 604D1DCE 509C0C23 99 1 99 D97F8571 A66CB41A -99 99 1 7822309D 64300984 99 99 99 D7F376F0 59BA89EB Successive calls to psdes with arguments 1 99 99 and 1 should produce exactly the lword and irword values shown. Masking conversion to a returned floating random value is allowed to be machine dependent values for VAX and PC are shown. CITED REFERENCES AND FURTHER READING Data Encryption Standard 1977 January 15 Federal Information Processing Standards Publication number 46 Washington . Department of Commerce National Bureau of Standards . 1 Guidelines for Implementing and Using the NBS Data Encryption Standard 1981 April 1 Federal Information Processing Standards Publication number 74 Washington . Department of Commerce National Bureau of Standards . 2 Validating the Correctness of Hardware Implementations ofthe NBS Data Encryption Standard 1980 NBS Special Publication 500-20 Washington . Department of Commerce National Bureau of Standards . 3 Meyer . and Matyas . 1982 Cryptography A New Dimension in Computer Data Security New York Wiley . 4 Knuth . 1973 Sorting and Searching vol. 3 of The Art ofComputer Programming Reading MA Addison-Wesley Chapter 6. 5 Vitter . and Chen W-C. 1987 Design and Analysis of Coalesced Hashing New York Oxford University Press .