lib/builtins/powixf2.c

   1 /* ===-- powixf2.cpp - Implement __powixf2 ---------------------------------===
   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 __powixf2 for the compiler_rt library.
  11  *
  12  * ===----------------------------------------------------------------------===
  13  */
  14
  15 #if !_ARCH_PPC
  16
  17 #include "int_lib.h"
  18
  19 /* Returns: a ^ b */
  20
  21 COMPILER_RT_ABI long double
  22 __powixf2(long double a, si_int b)
  23 {
  24     const int recip = b < 0;
  25     long double r = 1;
  26     while (1)
  27     {
  28         if (b & 1)
  29             r *= a;
  30         b /= 2;
  31         if (b == 0)
  32             break;
  33         a *= a;
  34     }
  35     return recip ? 1/r : r;
  36 }
  37
  38 #endif