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

src/share/vm/runtime/sharedRuntimeMath.hpp@69ea58782b1a (annotated)

src/share/vm/runtime/sharedRuntimeMath.hpp

Thu, 31 Jul 2014 19:59:36 +0200

author: roland
date: Thu, 31 Jul 2014 19:59:36 +0200
changeset 7003: 69ea58782b1a
parent 7002: a073be2ce5c2
permissions: -rw-r--r--

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

 /*
  * 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>
 // Used to access the lower/higher 32 bits of a double
 typedef union {
     double d;
     struct {
 #ifdef VM_LITTLE_ENDIAN
       int lo;
       int hi;
 #else
       int hi;
       int lo;
 #endif
     } split;
 } DoubleIntConv;
 static inline int high(double d) {
   DoubleIntConv x;
   x.d = d;
   return x.split.hi;
 }
 static inline int low(double d) {
   DoubleIntConv x;
   x.d = d;
   return x.split.lo;
 }
 static inline void set_high(double* d, int high) {
   DoubleIntConv conv;
   conv.d = *d;
   conv.split.hi = high;
   *d = conv.d;
 }
 static inline void set_low(double* d, int low) {
   DoubleIntConv conv;
   conv.d = *d;
   conv.split.lo = low;
   *d = conv.d;
 }
 static double copysignA(double x, double y) {
   DoubleIntConv convX;
   convX.d = x;
   convX.split.hi = (convX.split.hi & 0x7fffffff) | (high(y) & 0x80000000);
   return convX.d;
 }
 /*
  * ====================================================
  * 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 = high(x);
   lx = low(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 = high(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 */
     set_high(&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 */
   set_high(&x, (hx&0x800fffff)|(k<<20));
   return x*twom54;
 }
 #endif // SHARE_VM_RUNTIME_SHAREDRUNTIMEMATH_HPP

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src/share/vm/runtime/sharedRuntimeMath.hpp@69ea58782b1a (annotated)

src/share/vm/runtime/sharedRuntimeMath.hpp