mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-25 14:30:06 +00:00
90f0ac10a7
C2X adds new <math.h> functions for floating-point maximum and minimum, corresponding to the new operations that were added in IEEE 754-2019 because of concerns about the old operations not being associative in the presence of signaling NaNs. fmaximum and fminimum handle NaNs like most <math.h> functions (any NaN argument means the result is a quiet NaN). fmaximum_num and fminimum_num handle both quiet and signaling NaNs the way fmax and fmin handle quiet NaNs (if one argument is a number and the other is a NaN, return the number), but still raise "invalid" for a signaling NaN argument, making them exceptions to the normal rule that a function with a floating-point result raising "invalid" also returns a quiet NaN. fmaximum_mag, fminimum_mag, fmaximum_mag_num and fminimum_mag_num are corresponding functions returning the argument with greatest or least absolute value. All these functions also treat +0 as greater than -0. There are also corresponding <tgmath.h> type-generic macros. Add these functions to glibc. The implementations use type-generic templates based on those for fmax, fmin, fmaxmag and fminmag, and test inputs are based on those for those functions with appropriate adjustments to the expected results. The RISC-V maintainers might wish to add optimized versions of fmaximum_num and fminimum_num (for float and double), since RISC-V (F extension version 2.2 and later) provides instructions corresponding to those functions - though it might be at least as useful to add architecture-independent built-in functions to GCC and teach the RISC-V back end to expand those functions inline, which is what you generally want for functions that can be implemented with a single instruction. Tested for x86_64 and x86, and with build-many-glibcs.py.
34 lines
1.1 KiB
C
34 lines
1.1 KiB
C
/* Return minimum of X and Y.
|
|
Copyright (C) 1997-2021 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
|
|
<https://www.gnu.org/licenses/>. */
|
|
|
|
#include <math.h>
|
|
|
|
FLOAT
|
|
M_DECL_FUNC (__fminimum) (FLOAT x, FLOAT y)
|
|
{
|
|
if (isless (x, y))
|
|
return x;
|
|
else if (isgreater (x, y))
|
|
return y;
|
|
else if (x == y)
|
|
return (M_COPYSIGN (1, x) <= M_COPYSIGN (1, y) ? x : y);
|
|
else
|
|
return x + y;
|
|
}
|
|
declare_mgen_alias (__fminimum, fminimum);
|