1 /* 2 * Copyright (c) 2002, 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. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, 20 * CA 94065 USA or visit www.oracle.com if you need additional information or 21 * have any questions. 22 * 23 */ 24 25 package sun.jvm.hotspot.asm.sparc; 26 27 import sun.jvm.hotspot.asm.RTLDataTypes; 28 29 class RegisterDecoder implements /* imports */ RTLDataTypes { 30 // refer to page 40 - section 5.1.4.1 - Floating-point Register Number Encoding 31 private static SPARCFloatRegister decodeDouble(int num) { 32 // 6 bit double precision registers are encoded in 5 bits as 33 // b<4> b<3> b<2> b<1> b<5>. 34 35 boolean lsb = (0x1 & num) != 0; 36 if (lsb) 37 num |= 0x20; // 10000b 38 39 if ((num % 2) != 0) 40 return null; 41 42 return SPARCFloatRegisters.getRegister(num); 43 } 44 45 private static SPARCFloatRegister decodeQuad(int num) { 46 // 6 bit quad precision registers are encoded in 5 bits as 47 // b<4> b<3> b<2> 0 b<5> 48 49 boolean lsb = (0x1 & num) != 0; 50 if (lsb) 51 num |= 0x20; // 10000b 52 53 if ((num % 4) != 0) 54 return null; 55 56 return SPARCFloatRegisters.getRegister(num); 57 } 58 59 static SPARCRegister decode(int dataType, int regNum) { 60 regNum &= 0x1F; // mask out all but lsb 5 bits 61 SPARCRegister result = null; 62 switch (dataType) { 63 case RTLDT_FL_SINGLE: 64 result = SPARCFloatRegisters.getRegister(regNum); 65 break; 66 67 case RTLDT_FL_DOUBLE: 68 result = decodeDouble(regNum); 69 break; 70 71 case RTLDT_FL_QUAD: 72 result = decodeQuad(regNum); 73 break; 74 75 case RTLDT_UNKNOWN: 76 result = null; 77 break; 78 79 default: // some integer register 80 result = SPARCRegisters.getRegister(regNum); 81 break; 82 } 83 return result; 84 } 85 }