1 /* ===-- powidf2.cpp - Implement __powidf2 ---------------------------------===
2 *
3 * The LLVM Compiler Infrastructure
4 *
5 * This file is dual licensed under the MIT and the University of Illinois Open
6 * Source Licenses. See LICENSE.TXT for details.
7 *
8 * ===----------------------------------------------------------------------===
9 *
10 * This file implements __powidf2 for the compiler_rt library.
11 *
12 * ===----------------------------------------------------------------------===
13 */
14
15 #include "int_lib.h"
16
17 /* Returns: a ^ b */
18
19 COMPILER_RT_ABI double
__powidf2(double a,si_int b)20 __powidf2(double a, si_int b)
21 {
22 const int recip = b < 0;
23 double r = 1;
24 while (1)
25 {
26 if (b & 1)
27 r *= a;
28 b /= 2;
29 if (b == 0)
30 break;
31 a *= a;
32 }
33 return recip ? 1/r : r;
34 }
35