glibc/sysdeps/alpha/fpu/s_rintf.c

51 lines
1.5 KiB
C

/* Copyright (C) 2000-2017 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Richard Henderson.
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>
float
__rintf (float x)
{
if (isnanf (x))
return x + x;
if (isless (fabsf (x), 16777216.0f)) /* 1 << FLT_MANT_DIG */
{
/* Note that Alpha S_Floating is stored in registers in a
restricted T_Floating format, so we don't even need to
convert back to S_Floating in the end. The initial
conversion to T_Floating is needed to handle denormals. */
float tmp1, tmp2, new_x;
__asm ("cvtst/s %3,%2\n\t"
"cvttq/svid %2,%1\n\t"
"cvtqt/d %1,%0\n\t"
: "=f"(new_x), "=&f"(tmp1), "=&f"(tmp2)
: "f"(x));
/* rint(-0.1) == -0, and in general we'll always have the same
sign as our input. */
x = copysignf(new_x, x);
}
return x;
}
weak_alias (__rintf, rintf)