Fortran Tausworthe pseudorandom number generator

Intermediate computations in an “Extremely Portable Random Number Generator” by J. B. Kruskal [Comm. ACM 12, 2 (Feb. 1969), 93-94] exceed 15 bits plus sign. This is a severe limitation since the majority of small computers uses a 16 bit (15 bits plus sign) word or less. ASA standard FORTRAN compilers for these machines are readily available. Fortunately, a linearly recurring sequence generator [2] can be written in somewhat “portable” ASA Standard FORTRAN which will produce maximum length [2** (word size of computer - 1) -1] pseudorandom numbers for common 12, 16, 18, 24, and 32 bit computers, to mention only a few. Following Kendall's algorithm and notation presented by Whittlesey for a p-bit computer: p = 12, N = 11, M = 2; p = 16, N = 15, M = 1, 4, or 7; p = 18, N = 17, M = 3, 5, or 6; p = 24, N = 23, M = 5 or 9; and p = 32, N = 31, M = 3, 6, 7, or 13.

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