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59 lines
1.7 KiB
C
59 lines
1.7 KiB
C
/* Copyright (C) 1998, 1999, 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, 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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/* Use the -inf rounding mode conversion instructions to implement
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floor. We note when the exponent is large enough that the value
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must be integral, as this avoids unpleasant integer overflows. */
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double
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__floor (double x)
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{
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if (isless (fabs (x), 9007199254740992.0)) /* 1 << DBL_MANT_DIG */
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{
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double tmp1, new_x;
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__asm (
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#ifdef _IEEE_FP_INEXACT
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"cvttq/svim %2,%1\n\t"
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#else
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"cvttq/svm %2,%1\n\t"
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#endif
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"cvtqt/m %1,%0\n\t"
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: "=f"(new_x), "=&f"(tmp1)
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: "f"(x));
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/* floor(-0) == -0, and in general we'll always have the same
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sign as our input. */
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x = copysign(new_x, x);
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}
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return x;
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}
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weak_alias (__floor, floor)
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#ifdef NO_LONG_DOUBLE
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strong_alias (__floor, __floorl)
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weak_alias (__floor, floorl)
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#endif
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#if LONG_DOUBLE_COMPAT(libm, GLIBC_2_0)
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compat_symbol (libm, __floor, floorl, GLIBC_2_0);
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#endif
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