fix docs
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primes32.tal
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primes32.tal
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( primes32.tal )
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( )
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( primes32.tal )
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( )
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( Uses a simple trial-divion method to find primes. )
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( )
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( )
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( To determine if x is prime we: )
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( 1. Check if x is 2 (prime) )
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( 2. Check if x is even (not prime) )
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( 3. Starting with i=3, we see if x%i is 0 )
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( a. We increment i by 2 to avoid even i )
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( 3. Check if x is 3 (prime) )
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( 4. Starting with i=5, we see if x%i is 0 )
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( a. We alternately increment i by 2 and 4 )
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( b. We stop when x < i*i or i=0xffff )
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( 4. If we didn't find an i, x is prime. )
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( )
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( 5. If we didn't find an i, x is prime. )
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( )
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( The reason we alternate our increment is because we )
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( know that x%6 must equal 1 or 5. if x%6 was 3 then x )
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( would be divisible by 3. )
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( )
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( This method can be fast for some large composite )
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( numbers but is slower for large primes. )
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( )
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( )
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( On my machine, checking 0x7fffffff took 0.5 seconds )
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( and checking 0xfffffffb took 0.9 seconds. Both are )
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( prime numbers. )
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( )
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( )
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( Smaller primes also run fairly quickly: 0x17b5d was )
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( determined to be prime in 0.02 seconds. )
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@ -32,7 +37,7 @@
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#fffe #0001
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OVR2 OVR2 ;is-prime32 JSR2 ( test for primality )
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STH ;emit-long JSR2 SPACE STHr EMIT-BYTE NEWLINE ( output )
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#00 DIV #00 ( exit with /0 to make timing easier )
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#00 #00 DIV ( exit with /0 to make timing easier )
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BRK
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( include 32-bit math library )
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