57 lines
1.9 KiB
C
57 lines
1.9 KiB
C
/* Copyright (C) 1998, 1999, 2000 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 Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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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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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <math.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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float
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__floorf (float x)
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{
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if (isless (fabsf (x), 16777216.0f)) /* 1 << FLT_MANT_DIG */
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{
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/* Note that Alpha S_Floating is stored in registers in a
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restricted T_Floating format, so we don't even need to
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convert back to S_Floating in the end. The initial
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conversion to T_Floating is needed to handle denormals. */
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float tmp1, tmp2, new_x;
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__asm ("cvtst/s %3,%2\n\t"
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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), "=&f"(tmp2)
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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 = copysignf(new_x, x);
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}
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return x;
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}
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weak_alias (__floorf, floorf)
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