diff options
Diffstat (limited to 'sysdeps/ieee754/ldbl-128ibm/s_lroundl.c')
| -rw-r--r-- | sysdeps/ieee754/ldbl-128ibm/s_lroundl.c | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/sysdeps/ieee754/ldbl-128ibm/s_lroundl.c b/sysdeps/ieee754/ldbl-128ibm/s_lroundl.c new file mode 100644 index 0000000000..a5251eece0 --- /dev/null +++ b/sysdeps/ieee754/ldbl-128ibm/s_lroundl.c @@ -0,0 +1,142 @@ +/* Round to long int long double floating-point values. + IBM extended format long double version. + Copyright (C) 2006 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. */ + +#include <math.h> +#include <fenv_libc.h> +#include <math_ldbl_opt.h> +#include <float.h> +#include <ieee754.h> + +#ifdef __STDC__ +long +__lroundl (long double x) +#else +long +__lroundl (x) + long double x; +#endif +{ + double xh, xl; + long res, hi, lo; + + ldbl_unpack (x, &xh, &xl); + + /* Limit the range of values handled by the conversion to long. + We do this because we aren't sure whether that conversion properly + raises FE_INVALID. */ + if ( +#if __LONG_MAX__ == 2147483647 + __builtin_expect + ((__builtin_fabs (xh) <= (double) __LONG_MAX__ + 2), 1) +#else + __builtin_expect + ((__builtin_fabs (xh) <= -(double) (-__LONG_MAX__ - 1)), 1) +#endif +#if !defined (FE_INVALID) + || 1 +#endif + ) + { +#if __LONG_MAX__ == 2147483647 + long long llhi = (long long) xh; + if (llhi != (long) llhi) + hi = llhi < 0 ? -__LONG_MAX__ - 1 : __LONG_MAX__; + else + hi = llhi; + xh -= hi; +#else + if (__builtin_expect ((xh == -(double) (-__LONG_MAX__ - 1)), 0)) + { + /* When XH is 9223372036854775808.0, converting to long long will + overflow, resulting in an invalid operation. However, XL might + be negative and of sufficient magnitude that the overall long + double is in fact in range. Avoid raising an exception. In any + case we need to convert this value specially, because + the converted value is not exactly represented as a double + thus subtracting HI from XH suffers rounding error. */ + hi = __LONG_MAX__; + xh = 1.0; + } + else + { + hi = (long) xh; + xh -= hi; + } +#endif + ldbl_canonicalize (&xh, &xl); + + lo = (long) xh; + + /* Peg at max/min values, assuming that the above conversions do so. + Strictly speaking, we can return anything for values that overflow, + but this is more useful. */ + res = hi + lo; + + /* This is just sign(hi) == sign(lo) && sign(res) != sign(hi). */ + if (__builtin_expect (((~(hi ^ lo) & (res ^ hi)) < 0), 0)) + goto overflow; + + xh -= lo; + ldbl_canonicalize (&xh, &xl); + + hi = res; + if (xh > 0.5) + { + res += 1; + } + else if (xh == 0.5) + { + if (xl > 0.0 || (xl == 0.0 && res >= 0)) + res += 1; + } + else if (-xh > 0.5) + { + res -= 1; + } + else if (-xh == 0.5) + { + if (xl < 0.0 || (xl == 0.0 && res <= 0)) + res -= 1; + } + + if (__builtin_expect (((~(hi ^ (res - hi)) & (res ^ hi)) < 0), 0)) + goto overflow; + + return res; + } + else + { + if (xh > 0.0) + hi = __LONG_MAX__; + else if (xh < 0.0) + hi = -__LONG_MAX__ - 1; + else + /* Nan */ + hi = 0; + } + +overflow: +#ifdef FE_INVALID + feraiseexcept (FE_INVALID); +#endif + return hi; +} + +long_double_symbol (libm, __lroundl, lroundl); |