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8a9fa0086d
The ldbl-128ibm implementation of ceill is only correct in round-to-nearest mode (in other modes, there are incorrect results and overflow exceptions in some cases). It is also unnecessarily complicated, rounding both high and low parts to the nearest integer and then adjusting for the semantics of ceil, when it seems more natural to take the ceiling of the high part (__ceil optimized inline versions can be used), and that of the low part if the high part is an integer, as was done for floorl. This patch makes it use that simpler approach. Tested for powerpc. [BZ #19592] * sysdeps/ieee754/ldbl-128ibm/s_ceill.c (__ceill): Use __ceil on high and low parts then use ldbl_canonicalize_int if needed.
60 lines
1.6 KiB
C
60 lines
1.6 KiB
C
/* Ceil (round to +inf) long double floating-point values.
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IBM extended format long double version.
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Copyright (C) 2006-2016 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <math.h>
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#include <math_ldbl_opt.h>
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#include <float.h>
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#include <ieee754.h>
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long double
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__ceill (long double x)
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{
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double xh, xl, hi, lo;
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ldbl_unpack (x, &xh, &xl);
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/* Return Inf, Nan, +/-0 unchanged. */
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if (__builtin_expect (xh != 0.0
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&& __builtin_isless (__builtin_fabs (xh),
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__builtin_inf ()), 1))
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{
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hi = __ceil (xh);
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if (hi != xh)
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{
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/* The high part is not an integer; the low part does not
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affect the result. */
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xh = hi;
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xl = 0;
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}
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else
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{
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/* The high part is a nonzero integer. */
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lo = __ceil (xl);
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xh = hi;
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xl = lo;
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ldbl_canonicalize_int (&xh, &xl);
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}
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}
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return ldbl_pack (xh, xl);
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}
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long_double_symbol (libm, __ceill, ceill);
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