blob: 5da08ae1079e1adcf92572ea3d813909a3cc37aa [file] [log] [blame]
/* Copyright (C) 1998, 1999, 2000, 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>
/* Use the -inf rounding mode conversion instructions to implement
floor. We note when the exponent is large enough that the value
must be integral, as this avoids unpleasant integer overflows. */
float
__floorf (float 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"
#ifdef _IEEE_FP_INEXACT
"cvttq/svim %2,%1\n\t"
#else
"cvttq/svm %2,%1\n\t"
#endif
"cvtqt/m %1,%0\n\t"
: "=f"(new_x), "=&f"(tmp1), "=&f"(tmp2)
: "f"(x));
/* floor(-0) == -0, and in general we'll always have the same
sign as our input. */
x = copysignf(new_x, x);
}
return x;
}
weak_alias (__floorf, floorf)