54 lines
1.7 KiB
C
54 lines
1.7 KiB
C
/* Copyright (C) 1998, 2000, 2006, 2007 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Richard Henderson.
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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, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#include <math.h>
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#include <math_ldbl_opt.h>
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/* Use the -inf rounding mode conversion instructions to implement
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ceil, via something akin to -floor(-x). This is much faster than
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playing with the fpcr to achieve +inf rounding mode. */
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double
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__ceil (double x)
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{
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double two52 = copysign (0x1.0p52, x);
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double r, tmp;
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__asm (
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#ifdef _IEEE_FP_INEXACT
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"addt/suim %2, %3, %1\n\tsubt/suim %1, %3, %0"
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#else
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"addt/sum %2, %3, %1\n\tsubt/sum %1, %3, %0"
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#endif
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: "=&f"(r), "=&f"(tmp)
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: "f"(-x), "f"(-two52));
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/* Fix up the negation we did above, as well as handling -0 properly. */
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return copysign (r, x);
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}
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weak_alias (__ceil, ceil)
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#ifdef NO_LONG_DOUBLE
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strong_alias (__ceil, __ceill)
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weak_alias (__ceil, ceill)
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#endif
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#if LONG_DOUBLE_COMPAT(libm, GLIBC_2_0)
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compat_symbol (libm, __ceil, ceill, GLIBC_2_0);
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#endif
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