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(module |
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;; add the $even_check function to the top of the module |
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(func $even_check (param $n i32) (result i32) |
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local.get $n |
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i32.const 2 |
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i32.rem_u ;; if you take the remainder of a division by 2 |
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i32.const 0 ;; even numbers will have a remainder 0 |
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i32.eq ;; $n % 2 == 0 |
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) |
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;; add the $eq_2 function after $even_check |
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(func $eq_2 (param $n i32) (result i32) |
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local.get $n |
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i32.const 2 |
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i32.eq ;; returns 1 if $n == 2 |
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) |
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|
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;; add $multiple_check after $eq_2 |
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(func $multiple_check (param $n i32) (param $m i32) (result i32) |
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local.get $n |
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local.get $m |
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i32.rem_u ;; get the remainder of $n / $m |
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i32.const 0 ;; I want to know if the remainder is 0 |
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i32.eq ;; that will tell us if $n is a multiple of $m |
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) |
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|
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;; add the is_prime exported function after $multiple_check |
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(func (export "is_prime") (param $n i32) (result i32) |
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(local $i i32) |
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(if (i32.eq (local.get $n) (i32.const 1)) ;; 1 is not prime |
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(then |
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i32.const 0 |
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return |
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)) |
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(if (call $eq_2 (local.get $n)) ;; check to see if $n is 2 |
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(then |
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i32.const 1 ;; 2 is prime |
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return |
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) |
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) |
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(block $not_prime |
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(call $even_check (local.get $n)) |
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br_if $not_prime ;; even numbers are not prime (except 2) |
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|
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(local.set $i (i32.const 1)) |
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(loop $prime_test_loop |
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|
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(local.tee $i (i32.add (local.get $i) (i32.const 2) ) ) ;; $i += 2 |
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local.get $n ;; stack = [$n, $i] |
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|
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i32.ge_u ;; $i >= $n |
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if ;; if $i >= $n, $n is prime |
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i32.const 1 |
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return |
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end |
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(call $multiple_check (local.get $n) (local.get $i)) |
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br_if $not_prime ;; if $n is a multiple of $i this is not prime |
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br $prime_test_loop ;; branch back to top of loop |
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) ;; end of $prime_test_loop loop |
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) ;; end of $not_prime block |
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|
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i32.const 0 ;; return false |
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) |
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) ;; end of module |
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|
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;; From https://github.com/battlelinegames/ArtOfWasm/blob/main/Chapter3/is_prime.wat |
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