glibc/sysdeps/alpha/fpu/s_roundf.c

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/* Copyright (C) 2007 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, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <math.h>
float
__roundf (float x)
{
const float almost_half = 0x1.fffffep-2;
const float two23 = 0x1.0p23;
float r, tmp;
__asm (
#ifdef _IEEE_FP_INEXACT
"adds/suic %2, %3, %1\n\tsubs/suic %1, %3, %0"
#else
"adds/suc %2, %3, %1\n\tsubs/suc %1, %3, %0"
#endif
: "=&f"(r), "=&f"(tmp)
: "f"(fabsf (x) + almost_half), "f"(two23));
/* round(-0) == -0, and in general we'll always have the same
sign as our input. */
return copysignf (r, x);
}
weak_alias (__roundf, roundf)