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 initIDs()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 */ doubleToLongBits(double value)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 */ doubleToRawLongBits(double value)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 */ longBitsToDouble(long bits)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 */ toString(double d, boolean isFloat)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 */ initIDs()128 public static native void initIDs(); 129 parseDouble(String str)130 public static native double parseDouble(String str); 131 } 132