1 /* VMDouble.java -- VM Specific Double methods
2 Copyright (C) 2003, 2005 Free Software Foundation
3
4 This file is part of GNU Classpath.
5
6 GNU Classpath is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
9 any later version.
10
11 GNU Classpath is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with GNU Classpath; see the file COPYING. If not, write to the
18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
19 02110-1301 USA.
20
21 Linking this library statically or dynamically with other modules is
22 making a combined work based on this library. Thus, the terms and
23 conditions of the GNU General Public License cover the whole
24 combination.
25
26 As a special exception, the copyright holders of this library give you
27 permission to link this library with independent modules to produce an
28 executable, regardless of the license terms of these independent
29 modules, and to copy and distribute the resulting executable under
30 terms of your choice, provided that you also meet, for each linked
31 independent module, the terms and conditions of the license of that
32 module. An independent module is a module which is not derived from
33 or based on this library. If you modify this library, you may extend
34 this exception to your version of the library, but you are not
35 obligated to do so. If you do not wish to do so, delete this
36 exception statement from your version. */
37
38 package java.lang;
39
40 import gnu.classpath.Configuration;
41
42 /*
43 * This class is a reference version, mainly for compiling a class library
44 * jar. It is likely that VM implementers replace this with their own
45 * version that can communicate effectively with the VM.
46 */
47
48 /**
49 * Code relocated from java.lang.Double by
50 * @author Dave Grove (groved@us.ibm.com)
51 */
52 final class VMDouble
53 {
54
55 /**
56 * Load native routines necessary for this class.
57 */
58 static
59 {
60 if (Configuration.INIT_LOAD_LIBRARY)
61 {
62 System.loadLibrary("javalang");
63 }
64
65 initIDs();
66 }
67
68 /**
69 * Convert the double to the IEEE 754 floating-point "double format" bit
70 * layout. Bit 63 (the most significant) is the sign bit, bits 62-52
71 * (masked by 0x7ff0000000000000L) represent the exponent, and bits 51-0
72 * (masked by 0x000fffffffffffffL) are the mantissa. This function
73 * collapses all versions of NaN to 0x7ff8000000000000L. The result of this
74 * function can be used as the argument to
75 * <code>Double.longBitsToDouble(long)</code> to obtain the original
76 * <code>double</code> value.
77 *
78 * @param value the <code>double</code> to convert
79 * @return the bits of the <code>double</code>
80 * @see #longBitsToDouble(long)
81 */
82 public static native long doubleToLongBits(double value);
83
84 /**
85 * Convert the double to the IEEE 754 floating-point "double format" bit
86 * layout. Bit 63 (the most significant) is the sign bit, bits 62-52
87 * (masked by 0x7ff0000000000000L) represent the exponent, and bits 51-0
88 * (masked by 0x000fffffffffffffL) are the mantissa. This function
89 * leaves NaN alone, rather than collapsing to a canonical value. The
90 * result of this function can be used as the argument to
91 * <code>Double.longBitsToDouble(long)</code> to obtain the original
92 * <code>double</code> value.
93 *
94 * @param value the <code>double</code> to convert
95 * @return the bits of the <code>double</code>
96 * @see #longBitsToDouble(long)
97 */
98 public static native long doubleToRawLongBits(double value);
99
100 /**
101 * Convert the argument in IEEE 754 floating-point "double format" bit
102 * layout to the corresponding float. Bit 63 (the most significant) is the
103 * sign bit, bits 62-52 (masked by 0x7ff0000000000000L) represent the
104 * exponent, and bits 51-0 (masked by 0x000fffffffffffffL) are the mantissa.
105 * This function leaves NaN alone, so that you can recover the bit pattern
106 * with <code>Double.doubleToRawLongBits(double)</code>.
107 *
108 * @param bits the bits to convert
109 * @return the <code>double</code> represented by the bits
110 * @see #doubleToLongBits(double)
111 * @see #doubleToRawLongBits(double)
112 */
113 public static native double longBitsToDouble(long bits);
114
115 /**
116 * Helper method to convert to string.
117 *
118 * @param d the double to convert
119 * @param isFloat true if the conversion is requested by Float (results in
120 * fewer digits)
121 */
122 public static native String toString(double d, boolean isFloat);
123
124 /**
125 * Initialize JNI cache. This method is called only by the
126 * static initializer when using JNI.
127 */
128 public static native void initIDs();
129
130 public static native double parseDouble(String str);
131 }
Save This Page