---
title: Math.imul()
slug: Web/JavaScript/Reference/Global_Objects/Math/imul
tags:
  - JavaScript
  - Math
  - Method
  - Reference
translation_of: Web/JavaScript/Reference/Global_Objects/Math/imul
---
<div>{{JSRef}}</div>

<p><strong><code>Math.imul()</code></strong> 함수는 C 언어와 같은 양식으로 2개 파라메터의 32-bit 곱셈 결과를 리턴합니다.</p>

<h2 id="문법">문법</h2>

<pre class="syntaxbox"><code>Math.imul(<var>a</var>, <var>b</var>)</code></pre>

<h3 id="파라메터">파라메터</h3>

<dl>
 <dt><code>a</code></dt>
 <dd>첫 번째 숫자.</dd>
 <dt><code>b</code></dt>
 <dd>두 번째 숫자.</dd>
</dl>

<h2 id="설명">설명</h2>

<p><code>Math.imul()</code> 를 쓰면 C 언어와 같은 양식의 빠른 32-bit 정수 곱셈이 가능합니다. 이 기능은 <a href="http://en.wikipedia.org/wiki/Emscripten">Emscripten</a> 같은 프로젝트에 유용합니다. <code>imul()</code> 이 <code>Math </code> 객체의 정적 메소드이기 때문에, <code>Math 객체를 직접 만들어서 사용하지 않고 (Math 는 생성자가 아닙니다), Math.imul()</code> 같은 형태로 사용합니다.</p>

<h2 id="예제">예제</h2>

<h3 id="Math.imul()_사용법"><code>Math.imul() 사용법</code></h3>

<pre class="brush: js">Math.imul(2, 4);          // 8
Math.imul(-1, 8);         // -8
Math.imul(-2, -2);        // 4
Math.imul(0xffffffff, 5); // -5
Math.imul(0xfffffffe, 5); // -10
</pre>

<h2 id="Polyfill">Polyfill</h2>

<p>다음과 같은 함수로 Math.imul() 을 흉내낼 수 있습니다.</p>

<pre class="brush: js">Math.imul = Math.imul || function(a, b) {
  var ah = (a &gt;&gt;&gt; 16) &amp; 0xffff;
  var al = a &amp; 0xffff;
  var bh = (b &gt;&gt;&gt; 16) &amp; 0xffff;
  var bl = b &amp; 0xffff;
  // the shift by 0 fixes the sign on the high part
  // the final |0 converts the unsigned value into a signed value
  return ((al * bl) + (((ah * bl + al * bh) &lt;&lt; 16) &gt;&gt;&gt; 0)|0);
};
</pre>

<h2 id="스펙">스펙</h2>

<table class="standard-table">
 <tbody>
  <tr>
   <th scope="col">스펙</th>
   <th scope="col">상태</th>
   <th scope="col">비고</th>
  </tr>
  <tr>
   <td>{{SpecName('ES6', '#sec-math.imul', 'Math.imul')}}</td>
   <td>{{Spec2('ES6')}}</td>
   <td>초기 정의.</td>
  </tr>
  <tr>
   <td>{{SpecName('ESDraft', '#sec-math.imul', 'Math.imul')}}</td>
   <td>{{Spec2('ESDraft')}}</td>
   <td> </td>
  </tr>
 </tbody>
</table>

<h2 id="브라우저_호환성">브라우저 호환성</h2>

<div>{{CompatibilityTable}}</div>

<div id="compat-desktop">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Chrome</th>
   <th>Firefox (Gecko)</th>
   <th>Internet Explorer</th>
   <th>Opera</th>
   <th>Safari</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatChrome("28")}}</td>
   <td>{{CompatGeckoDesktop("20")}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatOpera("16")}}</td>
   <td>{{CompatSafari("7")}}</td>
  </tr>
 </tbody>
</table>
</div>

<div id="compat-mobile">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Android</th>
   <th>Chrome for Android</th>
   <th>Firefox Mobile (Gecko)</th>
   <th>IE Mobile</th>
   <th>Opera Mobile</th>
   <th>Safari Mobile</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatGeckoMobile("20")}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
   <td>7</td>
  </tr>
 </tbody>
</table>
</div>