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author | Thomas Schwinge <thomas@codesourcery.com> | 2013-04-02 13:51:02 +0200 |
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committer | Thomas Schwinge <thomas@codesourcery.com> | 2013-04-02 13:51:02 +0200 |
commit | 572676160d5639edc0ecb663147bd291841458d1 (patch) | |
tree | 26abea75b21e81f568075075249aa3dbedad20c7 /sysdeps/ieee754/dbl-64 | |
parent | 60c414c346a1d5ef0510ffbdc0ab75f288ee4d3f (diff) | |
download | glibc-572676160d5639edc0ecb663147bd291841458d1.tar.gz glibc-572676160d5639edc0ecb663147bd291841458d1.tar.xz glibc-572676160d5639edc0ecb663147bd291841458d1.zip |
New <math.h> macro named issignaling to check for a signaling NaN (sNaN).
It is based on draft TS 18661 and currently enabled as a GNU extension.
Diffstat (limited to 'sysdeps/ieee754/dbl-64')
-rw-r--r-- | sysdeps/ieee754/dbl-64/s_issignaling.c | 46 | ||||
-rw-r--r-- | sysdeps/ieee754/dbl-64/wordsize-64/s_issignaling.c | 43 |
2 files changed, 89 insertions, 0 deletions
diff --git a/sysdeps/ieee754/dbl-64/s_issignaling.c b/sysdeps/ieee754/dbl-64/s_issignaling.c new file mode 100644 index 0000000000..f475bc7bdf --- /dev/null +++ b/sysdeps/ieee754/dbl-64/s_issignaling.c @@ -0,0 +1,46 @@ +/* Test for signaling NaN. + Copyright (C) 2013 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> + +int +__issignaling (double x) +{ +#ifdef HIGH_ORDER_BIT_IS_SET_FOR_SNAN + u_int32_t hxi; + GET_HIGH_WORD (hxi, x); + /* We only have to care about the high-order bit of x's significand, because + having it set (sNaN) already makes the significand different from that + used to designate infinity. */ + return (hxi & 0x7ff80000) == 0x7ff80000; +#else + u_int32_t hxi, lxi; + EXTRACT_WORDS (hxi, lxi, x); + /* To keep the following comparison simple, toggle the quiet/signaling bit, + so that it is set for sNaNs. This is inverse to IEEE 754-2008 (as well as + common practice for IEEE 754-1985). */ + hxi ^= 0x00080000; + /* If lxi != 0, then set any suitable bit of the significand in hxi. */ + hxi |= (lxi | -lxi) >> 31; + /* We have to compare for greater (instead of greater or equal), because x's + significand being all-zero designates infinity not NaN. */ + return (hxi & 0x7fffffff) > 0x7ff80000; +#endif +} +libm_hidden_def (__issignaling) diff --git a/sysdeps/ieee754/dbl-64/wordsize-64/s_issignaling.c b/sysdeps/ieee754/dbl-64/wordsize-64/s_issignaling.c new file mode 100644 index 0000000000..3fa0254374 --- /dev/null +++ b/sysdeps/ieee754/dbl-64/wordsize-64/s_issignaling.c @@ -0,0 +1,43 @@ +/* Test for signaling NaN. + Copyright (C) 2013 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> + +int +__issignaling (double x) +{ + u_int64_t xi; + EXTRACT_WORDS64 (xi, x); +#ifdef HIGH_ORDER_BIT_IS_SET_FOR_SNAN +# error untested + /* We only have to care about the high-order bit of x's significand, because + having it set (sNaN) already makes the significand different from that + used to designate infinity. */ + return (xi & UINT64_C (0x7ff8000000000000)) == UINT64_C (0x7ff8000000000000); +#else + /* To keep the following comparison simple, toggle the quiet/signaling bit, + so that it is set for sNaNs. This is inverse to IEEE 754-2008 (as well as + common practice for IEEE 754-1985). */ + xi ^= UINT64_C (0x0008000000000000); + /* We have to compare for greater (instead of greater or equal), because x's + significand being all-zero designates infinity not NaN. */ + return (xi & UINT64_C (0x7fffffffffffffff)) > UINT64_C (0x7ff8000000000000); +#endif +} +libm_hidden_def (__issignaling) |