(module  (func (export "count1s") (param $num i32) (result i32)    ;; load the number onto the stack    local.get $num    ;; count the amount of 1s and return the result    i32.popcnt  ))

const url = "{%wasm-url%}";await WebAssembly.instantiateStreaming(fetch(url), { console }).then(  (result) => {    const count1s = result.instance.exports.count1s;    console.log(count1s(0b10000010));    // Expected output: 2  },);

;; load a number onto the stacki32.const 130 ;; 10000010;; count the 1si32.popcnt;; the top item on the stack will now be 2

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This page was last modified on⁨Nov 23, 2025⁩ byMDN contributors.