glibc/sysdeps/aarch64/fpu/s_lrint.c

89 lines
2.2 KiB
C

/* Copyright (C) 1996-2020 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>
#include <get-rounding-mode.h>
#include <stdint.h>
#include <math-barriers.h>
#include <libm-alias-double.h>
# define IREG_SIZE 64
# ifdef __ILP32__
# define OREG_SIZE 32
# else
# define OREG_SIZE 64
# endif
# define IREGS "d"
#if OREG_SIZE == 32
# define OREGS "w"
#else
# define OREGS "x"
#endif
long int
__lrint (double x)
{
#if IREG_SIZE == 64 && OREG_SIZE == 32
long int result;
if (__builtin_fabs (x) > INT32_MAX)
{
/* Converting large values to a 32 bit int may cause the frintx/fcvtza
sequence to set both FE_INVALID and FE_INEXACT. To avoid this
check the rounding mode and do a single instruction with the
appropriate rounding mode. */
switch (get_rounding_mode ())
{
case FE_TONEAREST:
asm volatile ("fcvtns" "\t%" OREGS "0, %" IREGS "1"
: "=r" (result) : "w" (x));
break;
case FE_UPWARD:
asm volatile ("fcvtps" "\t%" OREGS "0, %" IREGS "1"
: "=r" (result) : "w" (x));
break;
case FE_DOWNWARD:
asm volatile ("fcvtms" "\t%" OREGS "0, %" IREGS "1"
: "=r" (result) : "w" (x));
break;
case FE_TOWARDZERO:
default:
asm volatile ("fcvtzs" "\t%" OREGS "0, %" IREGS "1"
: "=r" (result) : "w" (x));
}
return result;
}
#endif
double r = __builtin_rint (x);
/* Prevent gcc from calling lrint directly when compiled with
-fno-math-errno by inserting a barrier. */
math_opt_barrier (r);
return r;
}
libm_alias_double (__lrint, lrint)