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/* Software floating-point emulation.
ilogbl(x, exp)
Copyright (C) 1999, 2012 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Jakub Jelinek (jj@ultra.linux.cz).
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
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
/* ilogbl(long double x)
* return the binary exponent of non-zero x
* ilogbl(0) = 0x80000001
* ilogbl(inf/NaN) = 0x7fffffff (no signal is raised)
*/
#include "soft-fp.h"
#include "quad.h"
#include <math.h>
int __ieee754_ilogbl (long double x)
{
FP_DECL_EX;
FP_DECL_Q(X);
/*
FP_UNPACK_Q(X, x);
switch (X_c)
{
case FP_CLS_ZERO:
return FP_ILOGB0;
case FP_CLS_NAN:
case FP_CLS_INF:
return FP_ILOGBNAN;
default:
return X_e;
}
*/
FP_UNPACK_RAW_Q(X, x);
switch (X_e)
{
default:
return X_e - _FP_EXPBIAS_Q;
case 0:
#if (2 * _FP_W_TYPE_SIZE) < _FP_FRACBITS_Q
if (_FP_FRAC_ZEROP_4(X))
return FP_ILOGB0;
else
{
_FP_I_TYPE shift;
_FP_FRAC_CLZ_4(shift, X);
shift -= _FP_FRACXBITS_Q;
return X_e - _FP_EXPBIAS_Q - 1 + shift;
}
#else
if (_FP_FRAC_ZEROP_2(X))
return FP_ILOGB0;
else
{
_FP_I_TYPE shift;
_FP_FRAC_CLZ_2(shift, X);
shift -= _FP_FRACXBITS_Q;
return X_e - _FP_EXPBIAS_Q - 1 + shift;
}
#endif
case _FP_EXPBIAS_Q:
return FP_ILOGBNAN;
}
}
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