1 /* VMFloat.java -- VM Specific Float methods
2 Copyright (C) 2003 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.Float by
50 * @author Dave Grove <groved@us.ibm.com>
51 */
52 final class VMFloat
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
66 /**
67 * Convert the float to the IEEE 754 floating-point "single format" bit
68 * layout. Bit 31 (the most significant) is the sign bit, bits 30-23
69 * (masked by 0x7f800000) represent the exponent, and bits 22-0
70 * (masked by 0x007fffff) are the mantissa. This function collapses all
71 * versions of NaN to 0x7fc00000. The result of this function can be used
72 * as the argument to <code>Float.intBitsToFloat(int)</code> to obtain the
73 * original <code>float</code> value.
74 *
75 * @param value the <code>float</code> to convert
76 * @return the bits of the <code>float</code>
77 * @see #intBitsToFloat(int)
78 */
79 static native int floatToIntBits(float value);
80
81 /**
82 * Convert the float to the IEEE 754 floating-point "single format" bit
83 * layout. Bit 31 (the most significant) is the sign bit, bits 30-23
84 * (masked by 0x7f800000) represent the exponent, and bits 22-0
85 * (masked by 0x007fffff) are the mantissa. This function leaves NaN alone,
86 * rather than collapsing to a canonical value. The result of this function
87 * can be used as the argument to <code>Float.intBitsToFloat(int)</code> to
88 * obtain the original <code>float</code> value.
89 *
90 * @param value the <code>float</code> to convert
91 * @return the bits of the <code>float</code>
92 * @see #intBitsToFloat(int)
93 */
94 static native int floatToRawIntBits(float value);
95
96 /**
97 * Convert the argument in IEEE 754 floating-point "single format" bit
98 * layout to the corresponding float. Bit 31 (the most significant) is the
99 * sign bit, bits 30-23 (masked by 0x7f800000) represent the exponent, and
100 * bits 22-0 (masked by 0x007fffff) are the mantissa. This function leaves
101 * NaN alone, so that you can recover the bit pattern with
102 * <code>Float.floatToRawIntBits(float)</code>.
103 *
104 * @param bits the bits to convert
105 * @return the <code>float</code> represented by the bits
106 * @see #floatToIntBits(float)
107 * @see #floatToRawIntBits(float)
108 */
109 static native float intBitsToFloat(int bits);
110
111 } // class VMFloat
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