lib/builtins/powidf2.c

/* ===-- powidf2.cpp - Implement __powidf2 ---------------------------------===
 *
 * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 * See https://llvm.org/LICENSE.txt for license information.
 * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 *
 * ===----------------------------------------------------------------------===
 *
 * This file implements __powidf2 for the compiler_rt library.
 *
 * ===----------------------------------------------------------------------===
 */

#include "int_lib.h"

/* Returns: a ^ b */

COMPILER_RT_ABI double
__powidf2(double a, si_int b)
{
    const int recip = b < 0;
    double r = 1;
    while (1)
    {
        if (b & 1)
            r *= a;
        b /= 2;
        if (b == 0)
            break;
        a *= a;
    }
    return recip ? 1/r : r;
}