/* Software floating-point emulation. ilogbl(x, exp) Copyright (C) 1999-2018 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 . */ /* 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 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; } }