popcnt: Wasm-Textanweisung
Die popcnt-Anweisungen, kurz für Population Count, werden verwendet, um die Anzahl von 1 in der binären Darstellung einer Zahl zu zählen.
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(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 }, ); Syntax
wat
;; load a number onto the stack i32.const 130 ;; 10000010 ;; count the 1s i32.popcnt ;; the top item on the stack will now be 2 | Anweisung | Binärer Opcode |
|---|---|
i32.popcnt | 0x69 |
i64.popcnt | 0x7b |