| /* Round to int long double floating-point values without raising inexact. |
| IBM extended format long double version. |
| Copyright (C) 2006, 2008 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, write to the Free |
| Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 USA. */ |
| |
| /* This has been coded in assembler because GCC makes such a mess of it |
| when it's coded in C. */ |
| |
| #include <math.h> |
| #include <fenv.h> |
| #include <math_ldbl_opt.h> |
| #include <float.h> |
| #include <ieee754.h> |
| |
| |
| #ifdef __STDC__ |
| long double |
| __nearbyintl (long double x) |
| #else |
| long double |
| __nearbyintl (x) |
| long double x; |
| #endif |
| { |
| fenv_t env; |
| static const long double TWO52 = 4503599627370496.0L; |
| union ibm_extended_long_double u; |
| u.d = x; |
| |
| if (fabs (u.dd[0]) < TWO52) |
| { |
| double high = u.dd[0]; |
| feholdexcept (&env); |
| if (high > 0.0) |
| { |
| high += TWO52; |
| high -= TWO52; |
| if (high == -0.0) high = 0.0; |
| } |
| else if (high < 0.0) |
| { |
| high -= TWO52; |
| high += TWO52; |
| if (high == 0.0) high = -0.0; |
| } |
| u.dd[0] = high; |
| u.dd[1] = 0.0; |
| fesetenv (&env); |
| } |
| else if (fabs (u.dd[1]) < TWO52 && u.dd[1] != 0.0) |
| { |
| double high, low, tau; |
| /* In this case we have to round the low double and handle any |
| adjustment to the high double that may be caused by rounding |
| (up). This is complicated by the fact that the high double |
| may already be rounded and the low double may have the |
| opposite sign to compensate. */ |
| feholdexcept (&env); |
| if (u.dd[0] > 0.0) |
| { |
| if (u.dd[1] > 0.0) |
| { |
| /* If the high/low doubles are the same sign then simply |
| round the low double. */ |
| high = u.dd[0]; |
| low = u.dd[1]; |
| } |
| else if (u.dd[1] < 0.0) |
| { |
| /* Else the high double is pre rounded and we need to |
| adjust for that. */ |
| |
| tau = __nextafter (u.dd[0], 0.0); |
| tau = (u.dd[0] - tau) * 2.0; |
| high = u.dd[0] - tau; |
| low = u.dd[1] + tau; |
| } |
| low += TWO52; |
| low -= TWO52; |
| } |
| else if (u.dd[0] < 0.0) |
| { |
| if (u.dd[1] < 0.0) |
| { |
| /* If the high/low doubles are the same sign then simply |
| round the low double. */ |
| high = u.dd[0]; |
| low = u.dd[1]; |
| } |
| else if (u.dd[1] > 0.0) |
| { |
| /* Else the high double is pre rounded and we need to |
| adjust for that. */ |
| tau = __nextafter (u.dd[0], 0.0); |
| tau = (u.dd[0] - tau) * 2.0; |
| high = u.dd[0] - tau; |
| low = u.dd[1] + tau; |
| } |
| low = TWO52 - low; |
| low = -(low - TWO52); |
| } |
| u.dd[0] = high + low; |
| u.dd[1] = high - u.dd[0] + low; |
| fesetenv (&env); |
| } |
| |
| return u.d; |
| } |
| |
| long_double_symbol (libm, __nearbyintl, nearbyintl); |