| /* Compute 2^x. |

| Copyright (C) 2012-2018 Free Software Foundation, Inc. |

| This file is part of the GNU C Library. |

| |

| The GNU C Library is free software; you can redistribute it and/or |

| modify it under the terms of the GNU Lesser General Public |

| License as published by the Free Software Foundation; either |

| version 2.1 of the License, or (at your option) any later version. |

| |

| The GNU C Library is distributed in the hope that it will be useful, |

| but WITHOUT ANY WARRANTY; without even the implied warranty of |

| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |

| Lesser General Public License for more details. |

| |

| You should have received a copy of the GNU Lesser General Public |

| License along with the GNU C Library; if not, see |

| <http://www.gnu.org/licenses/>. */ |

| |

| #include "quadmath-imp.h" |

| |

| __float128 |

| exp2q (__float128 x) |

| { |

| if (__glibc_likely (__builtin_isless (x, (__float128) FLT128_MAX_EXP))) |

| { |

| if (__builtin_expect (__builtin_isgreaterequal (x, (__float128) (FLT128_MIN_EXP - FLT128_MANT_DIG |

| - 1)), 1)) |

| { |

| int intx = (int) x; |

| __float128 fractx = x - intx; |

| __float128 result; |

| if (fabsq (fractx) < FLT128_EPSILON / 4) |

| result = scalbnq (1 + fractx, intx); |

| else |

| result = scalbnq (expq (M_LN2q * fractx), intx); |

| math_check_force_underflow_nonneg (result); |

| return result; |

| } |

| else |

| { |

| /* Underflow or exact zero. */ |

| if (isinfq (x)) |

| return 0; |

| else |

| return FLT128_MIN * FLT128_MIN; |

| } |

| } |

| else |

| /* Infinity, NaN or overflow. */ |

| return FLT128_MAX * x; |

| } |