計算前導零

(module

  (func (export "leading0") (param $num i32) (result i32)
    ;; load number onto the stack
    local.get $num

    ;; check how many leading zeros and return the result
    i32.clz
  )

)

const url = "{%wasm-url%}";
await WebAssembly.instantiateStreaming(fetch(url), { console }).then(
  (result) => {
    const leading0 = result.instance.exports.leading0;

    console.log(
      `Leading zeros: ${leading0(0b00000000_10000000_00000000_00000000)}`,
    );
    // Expected output: "Leading zeros: 8"
  },
);

;; load a number onto the stack
i32.const 8388608 ;; 00000000_10000000_00000000_00000000

;; count leading zeros
i32.clz

;; the top item on the stack will now be 8