34 lines
857 B
Plaintext
34 lines
857 B
Plaintext
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with TEXT_IO; use TEXT_IO;
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procedure SIEVE is
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ITERATIONS : constant := 10;
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SIZE : constant := 8190; -- 1024;
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type FLAG_TYPE is array (INTEGER range 0..SIZE) of BOOLEAN;
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PRIME, K, COUNT : INTEGER;
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FLAGS : FLAG_TYPE;
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begin
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PUT (INTEGER'IMAGE (ITERATIONS)); PUT_LINE (" iterations");
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for ITER in 1..ITERATIONS loop
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COUNT := 0;
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-- PUT ('.'); -- Should be commented out for accurate timing
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FLAGS := (others => TRUE);
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for I in FLAGS'RANGE loop
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if FLAGS (I) then
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PRIME := I + I + 3;
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K := I + PRIME;
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while K <= SIZE loop
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FLAGS (K) := FALSE;
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K := K + PRIME;
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end loop;
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COUNT := COUNT + 1;
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end if;
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end loop;
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end loop;
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PUT (INTEGER'IMAGE (COUNT)); PUT_LINE (" primes");
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end SIEVE;
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