/*

 * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code 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 General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#ifndef SHARE_VM_RUNTIME_SHAREDRUNTIMEMATH_HPP

#define SHARE_VM_RUNTIME_SHAREDRUNTIMEMATH_HPP

#include <math.h>

// VM_LITTLE_ENDIAN is #defined appropriately in the Makefiles

// [jk] this is not 100% correct because the float word order may different

// from the byte order (e.g. on ARM FPA)

#ifdef VM_LITTLE_ENDIAN

# define __HI(x) *(1+(int*)&x)

# define __LO(x) *(int*)&x

#else

# define __HI(x) *(int*)&x

# define __LO(x) *(1+(int*)&x)

#endif

static double copysignA(double x, double y) {

  __HI(x) = (__HI(x)&0x7fffffff)|(__HI(y)&0x80000000);

  return x;

}

/*

 * ====================================================

 * Copyright (c) 1998 Oracle and/or its affiliates. All rights reserved.

 *

 * Developed at SunSoft, a Sun Microsystems, Inc. business.

 * Permission to use, copy, modify, and distribute this

 * software is freely granted, provided that this notice

 * is preserved.

 * ====================================================

 */

/*

 * scalbn (double x, int n)

 * scalbn(x,n) returns x* 2**n  computed by  exponent

 * manipulation rather than by actually performing an

 * exponentiation or a multiplication.

 */

static const double

two54   =  1.80143985094819840000e+16, /* 0x43500000, 0x00000000 */

twom54  =  5.55111512312578270212e-17, /* 0x3C900000, 0x00000000 */

hugeX  = 1.0e+300,

tiny   = 1.0e-300;

static double scalbnA (double x, int n) {

  int  k,hx,lx;

  hx = __HI(x);

  lx = __LO(x);

  k = (hx&0x7ff00000)>>20;              /* extract exponent */

  if (k==0) {                           /* 0 or subnormal x */

    if ((lx|(hx&0x7fffffff))==0) return x; /* +-0 */

    x *= two54;

    hx = __HI(x);

    k = ((hx&0x7ff00000)>>20) - 54;

    if (n< -50000) return tiny*x;       /*underflow*/

  }

  if (k==0x7ff) return x+x;             /* NaN or Inf */

  k = k+n;

  if (k >  0x7fe) return hugeX*copysignA(hugeX,x); /* overflow  */

  if (k > 0)                            /* normal result */

    {__HI(x) = (hx&0x800fffff)|(k<<20); return x;}

  if (k <= -54) {

    if (n > 50000)      /* in case integer overflow in n+k */

      return hugeX*copysignA(hugeX,x);  /*overflow*/

    else return tiny*copysignA(tiny,x); /*underflow*/

  }

  k += 54;                              /* subnormal result */

  __HI(x) = (hx&0x800fffff)|(k<<20);

  return x*twom54;

}

#endif // SHARE_VM_RUNTIME_SHAREDRUNTIMEMATH_HPP