| /* Copyright (C) 2011-2018 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| Contributed by Ulrich Drepper <drepper@gmail.com>, 2011. |
| |
| 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 <inttypes.h> |
| #include <math.h> |
| #include <math_private.h> |
| #include <libm-alias-double.h> |
| |
| /* |
| * for non-zero, finite x |
| * x = frexp(arg,&exp); |
| * return a double fp quantity x such that 0.5 <= |x| <1.0 |
| * and the corresponding binary exponent "exp". That is |
| * arg = x*2^exp. |
| * If arg is inf, 0.0, or NaN, then frexp(arg,&exp) returns arg |
| * with *exp=0. |
| */ |
| |
| |
| double |
| __frexp (double x, int *eptr) |
| { |
| int64_t ix; |
| EXTRACT_WORDS64 (ix, x); |
| int32_t ex = 0x7ff & (ix >> 52); |
| int e = 0; |
| |
| if (__glibc_likely (ex != 0x7ff && x != 0.0)) |
| { |
| /* Not zero and finite. */ |
| e = ex - 1022; |
| if (__glibc_unlikely (ex == 0)) |
| { |
| /* Subnormal. */ |
| x *= 0x1p54; |
| EXTRACT_WORDS64 (ix, x); |
| ex = 0x7ff & (ix >> 52); |
| e = ex - 1022 - 54; |
| } |
| |
| ix = (ix & INT64_C (0x800fffffffffffff)) | INT64_C (0x3fe0000000000000); |
| INSERT_WORDS64 (x, ix); |
| } |
| else |
| /* Quiet signaling NaNs. */ |
| x += x; |
| |
| *eptr = e; |
| return x; |
| } |
| libm_alias_double (__frexp, frexp) |
