glibc/sysdeps/m68k/fpu/e_scalb.c

61 lines
1.7 KiB
C

/* Copyright (C) 1997, 1999 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Andreas Schwab <schwab@issan.informatik.uni-dortmund.de>.
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>
#include "math_private.h"
#include "mathimpl.h"
#ifndef SUFF
#define SUFF
#endif
#ifndef float_type
#define float_type double
#endif
#define CONCATX(a,b) __CONCAT(a,b)
#define s(name) CONCATX(name,SUFF)
#define m81(func) __m81_u(s(func))
float_type
s(__ieee754_scalb) (float_type x, float_type fn)
{
float_type retval;
unsigned long x_cond = __m81_test (x);
unsigned long fn_cond = __m81_test (fn);
if ((x_cond | fn_cond) & __M81_COND_NAN)
return x * fn;
if (fn_cond & __M81_COND_INF)
{
if (!(fn_cond & __M81_COND_NEG))
return x * fn;
else if (x_cond & __M81_COND_ZERO)
return x;
else
return x / -fn;
}
if (m81(__rint) (fn) != fn)
return (x - x) / (x - x);
__asm ("fscale%.x %1, %0" : "=f" (retval) : "f" (fn), "0" (x));
return retval;
}