glibc/sysdeps/m68k/fpu/s_frexpl.c

60 lines
1.7 KiB
C

/* Copyright (C) 2003 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, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <math.h>
long double
__frexpl (long double value, int *expptr)
{
long double mantissa, exponent;
int iexponent;
unsigned long fpsr;
__asm ("ftst%.x %1\n"
"fmove%.l %/fpsr, %0"
: "=dm" (fpsr) : "f" (value));
if (fpsr & (7 << 24))
{
/* Not finite or zero. */
*expptr = 0;
return value;
}
__asm ("fgetexp%.x %1, %0" : "=f" (exponent) : "f" (value));
iexponent = (int) exponent + 1;
*expptr = iexponent;
/* Unnormalized numbers must be handled specially, otherwise fscale
results in overflow. */
if (iexponent <= -16384)
{
value *= 0x1p16383L;
iexponent += 16383;
}
else if (iexponent >= 16384)
{
value *= 0x1p-16383L;
iexponent -= 16383;
}
__asm ("fscale%.l %2, %0"
: "=f" (mantissa)
: "0" (value), "dmi" (-iexponent));
return mantissa;
}
weak_alias (__frexpl, frexpl)