| /* Software floating-point emulation. |
| ilogbl(x, exp) |
| Copyright (C) 1999 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, write to the Free |
| Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 USA. */ |
| |
| /* 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 __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; |
| } |
| } |
| |
| weak_alias (__ilogbl, ilogbl) |
