jdk8-mips64-public/hotspot: src/share/vm/runtime/sharedRuntimeMath.hpp@69ea58782b1a

8054054: 8040121 is broken
Summary: C++ code pattern from 8040121 is incorrect
Reviewed-by: kvn

     1 /*

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

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

     4  *

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

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

     7  * published by the Free Software Foundation.

     8  *

     9  * This code is distributed in the hope that it will be useful, but WITHOUT

    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

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

    13  * accompanied this code).

    14  *

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

    16  * 2 along with this work; if not, write to the Free Software Foundation,

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

    18  *

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

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

    21  * questions.

    22  *

    23  */

    25 #ifndef SHARE_VM_RUNTIME_SHAREDRUNTIMEMATH_HPP

    26 #define SHARE_VM_RUNTIME_SHAREDRUNTIMEMATH_HPP

    28 #include <math.h>

    30 // Used to access the lower/higher 32 bits of a double

    31 typedef union {

    32     double d;

    33     struct {

    34 #ifdef VM_LITTLE_ENDIAN

    35       int lo;

    36       int hi;

    37 #else

    38       int hi;

    39       int lo;

    40 #endif

    41     } split;

    42 } DoubleIntConv;

    44 static inline int high(double d) {

    45   DoubleIntConv x;

    46   x.d = d;

    47   return x.split.hi;

    48 }

    50 static inline int low(double d) {

    51   DoubleIntConv x;

    52   x.d = d;

    53   return x.split.lo;

    54 }

    56 static inline void set_high(double* d, int high) {

    57   DoubleIntConv conv;

    58   conv.d = *d;

    59   conv.split.hi = high;

    60   *d = conv.d;

    61 }

    63 static inline void set_low(double* d, int low) {

    64   DoubleIntConv conv;

    65   conv.d = *d;

    66   conv.split.lo = low;

    67   *d = conv.d;

    68 }

    70 static double copysignA(double x, double y) {

    71   DoubleIntConv convX;

    72   convX.d = x;

    73   convX.split.hi = (convX.split.hi & 0x7fffffff) | (high(y) & 0x80000000);

    74   return convX.d;

    75 }

    77 /*

    78  * ====================================================

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

    80  *

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

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

    83  * software is freely granted, provided that this notice

    84  * is preserved.

    85  * ====================================================

    86  */

    88 /*

    89  * scalbn (double x, int n)

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

    91  * manipulation rather than by actually performing an

    92  * exponentiation or a multiplication.

    93  */

    95 static const double

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

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

    98 hugeX  = 1.0e+300,

    99 tiny   = 1.0e-300;

   101 static double scalbnA(double x, int n) {

   102   int  k,hx,lx;

   103   hx = high(x);

   104   lx = low(x);

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

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

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

   108     x *= two54;

   109     hx = high(x);

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

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

   112   }

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

   114   k = k+n;

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

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

   117     set_high(&x, (hx&0x800fffff)|(k<<20));

   118     return x;

   119   }

   120   if (k <= -54) {

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

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

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

   124   }

   125   k += 54;                              /* subnormal result */

   126   set_high(&x, (hx&0x800fffff)|(k<<20));

   127   return x*twom54;

   128 }

   130 #endif // SHARE_VM_RUNTIME_SHAREDRUNTIMEMATH_HPP

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