powidf2.c revision 353358 
1//===-- powidf2.cpp - Implement __powidf2 ---------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file implements __powidf2 for the compiler_rt library.
10//
11//===----------------------------------------------------------------------===//
12
13#include "int_lib.h"
14
15// Returns: a ^ b
16
17COMPILER_RT_ABI double __powidf2(double a, si_int b) {
18  const int recip = b < 0;
19  double r = 1;
20  while (1) {
21    if (b & 1)
22      r *= a;
23    b /= 2;
24    if (b == 0)
25      break;
26    a *= a;
27  }
28  return recip ? 1 / r : r;
29}
30