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 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
