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1 primes.i is a simple program for printing out a list of prime numbers.
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2 It has an outer loop variable .11 and an inner loop variable .13, both
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3 of which start at #3 and advance through odd numbers. .13 contains the
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4 numbers being tested as possible divisors of .11, which is the number
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5 being tested for primality. Each time through the inner loop a 16-bit
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6 division with remainder routine (2030) is called to divide .11 by .13.
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7 If .13 is greater than the quotient then .11 is known to be prime and
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8 is printed out. If the remainder is #0, on the other hand, then .11
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9 is known to be composite and the inner loop is terminated prematurely.
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10
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11 The termination test for the outer loop is controlled by statement (22),
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12 which tests to see if the high bit of (.11-#1)/#2 is set. You can
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13 modify this statement to test some other bit if you want the program
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14 to terminate sooner. It took over 17 hours on a Sparc 1 for this
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15 program to find all 16-bit primes.
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16
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17 Louis Howell
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18 December 30, 1991
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