glibc/math/math-underflow.h

80 lines
2.7 KiB
C

/* Check for underflow and force underflow exceptions.
Copyright (C) 2015-2023 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/>. */
#ifndef _MATH_UNDERFLOW_H
#define _MATH_UNDERFLOW_H 1
#include <float.h>
#include <math.h>
#include <math-barriers.h>
#define fabs_tg(x) __MATH_TG ((x), (__typeof (x)) __builtin_fabs, (x))
/* These must be function-like macros because some __MATH_TG
implementations macro-expand the function-name argument before
concatenating a suffix to it. */
#define min_of_type_f() FLT_MIN
#define min_of_type_() DBL_MIN
#define min_of_type_l() LDBL_MIN
#define min_of_type_f128() FLT128_MIN
#define min_of_type(x) __MATH_TG ((x), (__typeof (x)) min_of_type_, ())
/* If X (which is not a NaN) is subnormal, force an underflow
exception. */
#define math_check_force_underflow(x) \
do \
{ \
__typeof (x) force_underflow_tmp = (x); \
if (fabs_tg (force_underflow_tmp) \
< min_of_type (force_underflow_tmp)) \
{ \
__typeof (force_underflow_tmp) force_underflow_tmp2 \
= force_underflow_tmp * force_underflow_tmp; \
math_force_eval (force_underflow_tmp2); \
} \
} \
while (0)
/* Likewise, but X is also known to be nonnegative. */
#define math_check_force_underflow_nonneg(x) \
do \
{ \
__typeof (x) force_underflow_tmp = (x); \
if (force_underflow_tmp \
< min_of_type (force_underflow_tmp)) \
{ \
__typeof (force_underflow_tmp) force_underflow_tmp2 \
= force_underflow_tmp * force_underflow_tmp; \
math_force_eval (force_underflow_tmp2); \
} \
} \
while (0)
/* Likewise, for both real and imaginary parts of a complex
result. */
#define math_check_force_underflow_complex(x) \
do \
{ \
__typeof (x) force_underflow_complex_tmp = (x); \
math_check_force_underflow (__real__ force_underflow_complex_tmp); \
math_check_force_underflow (__imag__ force_underflow_complex_tmp); \
} \
while (0)
#endif /* math-underflow.h */