1 /* |
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2 * Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved. |
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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4 * |
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5 * This code is free software; you can redistribute it and/or modify it |
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6 * under the terms of the GNU General Public License version 2 only, as |
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7 * published by the Free Software Foundation. |
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8 * |
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9 * This code is distributed in the hope that it will be useful, but WITHOUT |
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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12 * version 2 for more details (a copy is included in the LICENSE file that |
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13 * accompanied this code). |
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14 * |
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15 * You should have received a copy of the GNU General Public License version |
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16 * 2 along with this work; if not, write to the Free Software Foundation, |
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17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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18 * |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
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22 * |
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23 */ |
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24 |
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25 package sun.jvm.hotspot.asm.sparc; |
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26 |
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27 import sun.jvm.hotspot.asm.*; |
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28 |
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29 // basic instruction decoder class |
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30 abstract class InstructionDecoder implements /* imports */ SPARCOpcodes , RTLDataTypes, RTLOperations { |
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31 // some general utility functions - for format 2, 3 & 3A instructions |
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32 |
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33 static int extractSignedIntFromNBits(int value, int num_bits) { |
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34 return (value << (32 - num_bits)) >> (32 - num_bits); |
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35 } |
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36 |
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37 // "rs1" |
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38 static int getSourceRegister1(int instruction) { |
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39 return (instruction & RS1_MASK) >>> RS1_START_BIT; |
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40 } |
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41 |
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42 // "rs2" |
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43 static int getSourceRegister2(int instruction) { |
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44 return (instruction & RS2_MASK); |
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45 } |
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46 |
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47 // "rd" |
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48 static int getDestinationRegister(int instruction) { |
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49 return (instruction & RD_MASK) >>> RD_START_BIT; |
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50 } |
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51 |
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52 static int getConditionCode(int instruction) { |
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53 return (instruction & CONDITION_CODE_MASK) >>> CONDITION_CODE_START_BIT; |
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54 } |
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55 |
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56 // "i" bit - used to indicate whether second component in an indirect |
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57 // address is immediate value or a register. (format 3 & 3A). |
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58 |
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59 static boolean isIBitSet(int instruction) { |
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60 return (instruction & I_MASK) != 0; |
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61 } |
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62 |
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63 static ImmediateOrRegister getOperand2(int instruction) { |
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64 boolean iBit = isIBitSet(instruction); |
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65 ImmediateOrRegister operand2 = null; |
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66 if (iBit) { |
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67 operand2 = new Immediate(new Short((short)extractSignedIntFromNBits(instruction, 13))); |
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68 } else { |
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69 operand2 = SPARCRegisters.getRegister(getSourceRegister2(instruction)); |
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70 } |
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71 return operand2; |
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72 } |
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73 |
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74 // "opf" - floating point operation code. |
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75 static int getOpf(int instruction) { |
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76 return (instruction & OPF_MASK) >>> OPF_START_BIT; |
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77 } |
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78 |
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79 abstract Instruction decode(int instruction, SPARCInstructionFactory factory); |
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80 } |
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