Retro68/gcc/libquadmath/math/lroundq.c

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/* Round long double value to long int.
Copyright (C) 1997-2018 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997 and
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Jakub Jelinek <jj@ultra.linux.cz>, 1999.
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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
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License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
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#include "quadmath-imp.h"
long int
lroundq (__float128 x)
{
int64_t j0;
uint64_t i1, i0;
long int result;
int sign;
GET_FLT128_WORDS64 (i0, i1, x);
j0 = ((i0 >> 48) & 0x7fff) - 0x3fff;
sign = (i0 & 0x8000000000000000ULL) != 0 ? -1 : 1;
i0 &= 0x0000ffffffffffffLL;
i0 |= 0x0001000000000000LL;
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if (j0 < (int32_t) (8 * sizeof (long int)) - 1)
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{
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if (j0 < 48)
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{
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if (j0 < 0)
return j0 < -1 ? 0 : sign;
else
{
i0 += 0x0000800000000000LL >> j0;
result = i0 >> (48 - j0);
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#ifdef FE_INVALID
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if (sizeof (long int) == 4
&& sign == 1
&& result == LONG_MIN)
/* Rounding brought the value out of range. */
feraiseexcept (FE_INVALID);
#endif
}
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}
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else if (j0 >= 112)
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result = ((long int) i0 << (j0 - 48)) | (i1 << (j0 - 112));
else
{
uint64_t j = i1 + (0x8000000000000000ULL >> (j0 - 48));
if (j < i1)
++i0;
if (j0 == 48)
result = (long int) i0;
else
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{
result = ((long int) i0 << (j0 - 48)) | (j >> (112 - j0));
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#ifdef FE_INVALID
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if (sizeof (long int) == 8
&& sign == 1
&& result == LONG_MIN)
/* Rounding brought the value out of range. */
feraiseexcept (FE_INVALID);
#endif
}
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}
}
else
{
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/* The number is too large. Unless it rounds to LONG_MIN,
FE_INVALID must be raised and the return value is
unspecified. */
#ifdef FE_INVALID
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if (FIX_FLT128_LONG_CONVERT_OVERFLOW
&& !(sign == -1 && x > (__float128) LONG_MIN - 0.5Q))
{
feraiseexcept (FE_INVALID);
return sign == 1 ? LONG_MAX : LONG_MIN;
}
else if (!FIX_FLT128_LONG_CONVERT_OVERFLOW
&& x <= (__float128) LONG_MIN - 0.5Q)
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{
/* If truncation produces LONG_MIN, the cast will not raise
the exception, but may raise "inexact". */
feraiseexcept (FE_INVALID);
return LONG_MIN;
}
#endif
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/* The number is too large. It is left implementation defined
what happens. */
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return (long int) x;
}
return sign * result;
}