| /* Emulation for ldexpl. |

| Contributed by Paolo Bonzini |

| |

| Copyright 2002-2003, 2007-2012 Free Software Foundation, Inc. |

| |

| This file is part of gnulib. |

| |

| This program is free software: you can redistribute it and/or modify |

| it under the terms of the GNU General Public License as published by |

| the Free Software Foundation; either version 3 of the License, or |

| (at your option) any later version. |

| |

| This program 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 General Public License for more details. |

| |

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

| along with this program. If not, see <http://www.gnu.org/licenses/>. */ |

| |

| #include <config.h> |

| |

| /* Specification. */ |

| #include <math.h> |

| |

| #if HAVE_SAME_LONG_DOUBLE_AS_DOUBLE |

| |

| long double |

| ldexpl (long double x, int exp) |

| { |

| return ldexp (x, exp); |

| } |

| |

| #else |

| |

| # include <float.h> |

| # include "fpucw.h" |

| |

| long double |

| ldexpl (long double x, int exp) |

| { |

| long double factor; |

| int bit; |

| DECL_LONG_DOUBLE_ROUNDING |

| |

| BEGIN_LONG_DOUBLE_ROUNDING (); |

| |

| /* Check for zero, nan and infinity. */ |

| if (!(isnanl (x) || x + x == x)) |

| { |

| if (exp < 0) |

| { |

| exp = -exp; |

| factor = 0.5L; |

| } |

| else |

| factor = 2.0L; |

| |

| if (exp > 0) |

| for (bit = 1;;) |

| { |

| /* Invariant: Here bit = 2^i, factor = 2^-2^i or = 2^2^i, |

| and bit <= exp. */ |

| if (exp & bit) |

| x *= factor; |

| bit <<= 1; |

| if (bit > exp) |

| break; |

| factor = factor * factor; |

| } |

| } |

| |

| END_LONG_DOUBLE_ROUNDING (); |

| |

| return x; |

| } |

| |

| #endif |

| |

| #if 0 |

| int |

| main (void) |

| { |

| long double x; |

| int y; |

| for (y = 0; y < 29; y++) |

| printf ("%5d %.16Lg %.16Lg\n", y, ldexpl (0.8L, y), ldexpl (0.8L, -y) * ldexpl (0.8L, y)); |

| } |

| #endif |