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      1 /*
      2  * Copyright (c) 1997, 2005, 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.  Oracle designates this
      8  * particular file as subject to the "Classpath" exception as provided
      9  * by Oracle in the LICENSE file that accompanied this code.
     10  *
     11  * This code is distributed in the hope that it will be useful, but WITHOUT
     12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
     13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
     14  * version 2 for more details (a copy is included in the LICENSE file that
     15  * accompanied this code).
     16  *
     17  * You should have received a copy of the GNU General Public License version
     18  * 2 along with this work; if not, write to the Free Software Foundation,
     19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
     20  *
     21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
     22  * or visit www.oracle.com if you need additional information or have any
     23  * questions.
     24  */
     25 
     26 #include "jni.h"
     27 #include "jni_util.h"
     28 #include "jlong.h"
     29 #include "jvm.h"
     30 
     31 #include "JNIHelp.h"
     32 
     33 #define NATIVE_METHOD(className, functionName, signature) \
     34 { #functionName, signature, (void*)(className ## _ ## functionName) }
     35 
     36 
     37 /*
     38  * Find the double float corresponding to a given bit pattern
     39  */
     40 JNIEXPORT jdouble JNICALL
     41 Double_longBitsToDouble(JNIEnv *env, jclass unused, jlong v)
     42 {
     43     union {
     44         jlong l;
     45         double d;
     46     } u;
     47     jlong_to_jdouble_bits(&v);
     48     u.l = v;
     49     return (jdouble)u.d;
     50 }
     51 
     52 /*
     53  * Find the bit pattern corresponding to a given double float, NOT collapsing NaNs
     54  */
     55 JNIEXPORT jlong JNICALL
     56 Double_doubleToRawLongBits(JNIEnv *env, jclass unused, jdouble v)
     57 {
     58     union {
     59         jlong l;
     60         double d;
     61     } u;
     62     jdouble_to_jlong_bits(&v);
     63     u.d = (double)v;
     64     return u.l;
     65 }
     66 static JNINativeMethod gMethods[] = {
     67   NATIVE_METHOD(Double, longBitsToDouble, "(J)D"),
     68   NATIVE_METHOD(Double, doubleToRawLongBits, "(D)J"),
     69 };
     70 
     71 void register_java_lang_Double(JNIEnv* env) {
     72   jniRegisterNativeMethods(env, "java/lang/Double", gMethods, NELEM(gMethods));
     73 }
     74