| /* Test whether long double value is canonical. ldbl-128ibm version. |
| Copyright (C) 2016-2018 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| |
| 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/>. */ |
| |
| #include <math.h> |
| #include <math_private.h> |
| #include <stdint.h> |
| |
| int |
| __iscanonicall (long double x) |
| { |
| double xhi, xlo; |
| uint64_t hx, lx; |
| |
| ldbl_unpack (x, &xhi, &xlo); |
| EXTRACT_WORDS64 (hx, xhi); |
| EXTRACT_WORDS64 (lx, xlo); |
| int64_t ix = hx & 0x7fffffffffffffffULL; |
| int64_t iy = lx & 0x7fffffffffffffffULL; |
| int hexp = (ix & 0x7ff0000000000000LL) >> 52; |
| int lexp = (iy & 0x7ff0000000000000LL) >> 52; |
| |
| if (iy == 0) |
| /* Low part 0 is always OK. */ |
| return 1; |
| |
| if (hexp == 0x7ff) |
| /* If a NaN, the low part does not matter. If an infinity, the |
| low part must be 0, in which case we have already returned. */ |
| return ix != 0x7ff0000000000000LL; |
| |
| /* The high part is finite and the low part is nonzero. There must |
| be sufficient difference between the exponents. */ |
| bool low_p2; |
| if (lexp == 0) |
| { |
| /* Adjust the exponent for subnormal low part. */ |
| lexp = 12 - __builtin_clzll (iy); |
| low_p2 = iy == (1LL << (51 + lexp)); |
| } |
| else |
| low_p2 = (iy & 0xfffffffffffffLL) == 0; |
| int expdiff = hexp - lexp; |
| return expdiff > 53 || (expdiff == 53 && low_p2 && (ix & 1) == 0); |
| } |
| libm_hidden_def (__iscanonicall) |
