lfoltan@7000: /*
lfoltan@7000:  * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
lfoltan@7000:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
lfoltan@7000:  *
lfoltan@7000:  * This code is free software; you can redistribute it and/or modify it
lfoltan@7000:  * under the terms of the GNU General Public License version 2 only, as
lfoltan@7000:  * published by the Free Software Foundation.
lfoltan@7000:  *
lfoltan@7000:  * This code is distributed in the hope that it will be useful, but WITHOUT
lfoltan@7000:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
lfoltan@7000:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
lfoltan@7000:  * version 2 for more details (a copy is included in the LICENSE file that
lfoltan@7000:  * accompanied this code).
lfoltan@7000:  *
lfoltan@7000:  * You should have received a copy of the GNU General Public License version
lfoltan@7000:  * 2 along with this work; if not, write to the Free Software Foundation,
lfoltan@7000:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
lfoltan@7000:  *
lfoltan@7000:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
lfoltan@7000:  * or visit www.oracle.com if you need additional information or have any
lfoltan@7000:  * questions.
lfoltan@7000:  *
lfoltan@7000:  */
lfoltan@7000: 
lfoltan@7000: #ifndef SHARE_VM_RUNTIME_SHAREDRUNTIMEMATH_HPP
lfoltan@7000: #define SHARE_VM_RUNTIME_SHAREDRUNTIMEMATH_HPP
lfoltan@7000: 
lfoltan@7000: #include <math.h>
lfoltan@7000: 
thartmann@7002: // Used to access the lower/higher 32 bits of a double
thartmann@7002: typedef union {
thartmann@7002:     double d;
thartmann@7002:     struct {
lfoltan@7000: #ifdef VM_LITTLE_ENDIAN
thartmann@7002:       int lo;
thartmann@7002:       int hi;
lfoltan@7000: #else
thartmann@7002:       int hi;
thartmann@7002:       int lo;
lfoltan@7000: #endif
thartmann@7002:     } split;
thartmann@7002: } DoubleIntConv;
thartmann@7002: 
thartmann@7002: static inline int high(double d) {
thartmann@7002:   DoubleIntConv x = { d };
thartmann@7002:   return x.split.hi;
thartmann@7002: }
thartmann@7002: 
thartmann@7002: static inline int low(double d) {
thartmann@7002:   DoubleIntConv x = { d };
thartmann@7002:   return x.split.lo;
thartmann@7002: }
thartmann@7002: 
thartmann@7002: static inline void set_high(double* d, int high) {
thartmann@7002:   DoubleIntConv conv = { *d };
thartmann@7002:   conv.split.hi = high;
thartmann@7002:   *d = conv.d;
thartmann@7002: }
thartmann@7002: 
thartmann@7002: static inline void set_low(double* d, int low) {
thartmann@7002:   DoubleIntConv conv = { *d };
thartmann@7002:   conv.split.lo = low;
thartmann@7002:   *d = conv.d;
thartmann@7002: }
lfoltan@7000: 
lfoltan@7000: static double copysignA(double x, double y) {
thartmann@7002:   DoubleIntConv convX = { x };
thartmann@7002:   convX.split.hi = (convX.split.hi & 0x7fffffff) | (high(y) & 0x80000000);
thartmann@7002:   return convX.d;
lfoltan@7000: }
lfoltan@7000: 
lfoltan@7000: /*
lfoltan@7000:  * ====================================================
lfoltan@7000:  * Copyright (c) 1998 Oracle and/or its affiliates. All rights reserved.
lfoltan@7000:  *
lfoltan@7000:  * Developed at SunSoft, a Sun Microsystems, Inc. business.
lfoltan@7000:  * Permission to use, copy, modify, and distribute this
lfoltan@7000:  * software is freely granted, provided that this notice
lfoltan@7000:  * is preserved.
lfoltan@7000:  * ====================================================
lfoltan@7000:  */
lfoltan@7000: 
lfoltan@7000: /*
lfoltan@7000:  * scalbn (double x, int n)
lfoltan@7000:  * scalbn(x,n) returns x* 2**n  computed by  exponent
lfoltan@7000:  * manipulation rather than by actually performing an
lfoltan@7000:  * exponentiation or a multiplication.
lfoltan@7000:  */
lfoltan@7000: 
lfoltan@7000: static const double
lfoltan@7000: two54   =  1.80143985094819840000e+16, /* 0x43500000, 0x00000000 */
lfoltan@7000: twom54  =  5.55111512312578270212e-17, /* 0x3C900000, 0x00000000 */
lfoltan@7000: hugeX  = 1.0e+300,
lfoltan@7000: tiny   = 1.0e-300;
lfoltan@7000: 
thartmann@7002: static double scalbnA(double x, int n) {
lfoltan@7000:   int  k,hx,lx;
thartmann@7002:   hx = high(x);
thartmann@7002:   lx = low(x);
lfoltan@7000:   k = (hx&0x7ff00000)>>20;              /* extract exponent */
lfoltan@7000:   if (k==0) {                           /* 0 or subnormal x */
lfoltan@7000:     if ((lx|(hx&0x7fffffff))==0) return x; /* +-0 */
lfoltan@7000:     x *= two54;
thartmann@7002:     hx = high(x);
lfoltan@7000:     k = ((hx&0x7ff00000)>>20) - 54;
lfoltan@7000:     if (n< -50000) return tiny*x;       /*underflow*/
lfoltan@7000:   }
lfoltan@7000:   if (k==0x7ff) return x+x;             /* NaN or Inf */
lfoltan@7000:   k = k+n;
thartmann@7002:   if (k > 0x7fe) return hugeX*copysignA(hugeX,x); /* overflow  */
thartmann@7002:   if (k > 0) {                          /* normal result */
thartmann@7002:     set_high(&x, (hx&0x800fffff)|(k<<20));
thartmann@7002:     return x;
thartmann@7002:   }
lfoltan@7000:   if (k <= -54) {
lfoltan@7000:     if (n > 50000)      /* in case integer overflow in n+k */
lfoltan@7000:       return hugeX*copysignA(hugeX,x);  /*overflow*/
lfoltan@7000:     else return tiny*copysignA(tiny,x); /*underflow*/
lfoltan@7000:   }
lfoltan@7000:   k += 54;                              /* subnormal result */
thartmann@7002:   set_high(&x, (hx&0x800fffff)|(k<<20));
lfoltan@7000:   return x*twom54;
lfoltan@7000: }
lfoltan@7000: 
lfoltan@7000: #endif // SHARE_VM_RUNTIME_SHAREDRUNTIMEMATH_HPP