1 /*
   2  * Copyright (c) 2019, 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, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 
  25 package org.graalvm.compiler.lir.amd64;
  26 
  27 import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.COMPOSITE;
  28 import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.REG;
  29 
  30 import org.graalvm.compiler.asm.amd64.AMD64MacroAssembler;
  31 import org.graalvm.compiler.core.common.LIRKind;
  32 import org.graalvm.compiler.lir.LIRInstructionClass;
  33 import org.graalvm.compiler.lir.Opcode;
  34 import org.graalvm.compiler.lir.asm.CompilationResultBuilder;
  35 
  36 import jdk.vm.ci.amd64.AMD64;
  37 import jdk.vm.ci.amd64.AMD64Kind;
  38 import jdk.vm.ci.code.RegisterValue;
  39 import jdk.vm.ci.meta.Value;
  40 
  41 /**
  42  * Zeros a chunk of memory using rep stosb.
  43  */
  44 @Opcode("ZERO_MEMORY")
  45 public final class AMD64ZeroMemoryOp extends AMD64LIRInstruction {
  46 
  47     public static final LIRInstructionClass<AMD64ZeroMemoryOp> TYPE = LIRInstructionClass.create(AMD64ZeroMemoryOp.class);
  48 
  49     @Use({COMPOSITE}) protected AMD64AddressValue pointer;
  50     @Use({REG}) protected RegisterValue length;
  51 
  52     @Temp protected Value pointerTemp;
  53     @Temp protected Value valueTemp;
  54     @Temp protected Value lengthTemp;
  55 
  56     public AMD64ZeroMemoryOp(AMD64AddressValue pointer, RegisterValue length) {
  57         super(TYPE);
  58         this.pointer = pointer;
  59         this.length = length;
  60 
  61         this.pointerTemp = AMD64.rdi.asValue(LIRKind.value(AMD64Kind.QWORD));
  62         this.valueTemp = AMD64.rax.asValue(LIRKind.value(AMD64Kind.QWORD));
  63         this.lengthTemp = AMD64.rcx.asValue(LIRKind.value(AMD64Kind.QWORD));
  64     }
  65 
  66     @Override
  67     public void emitCode(CompilationResultBuilder crb, AMD64MacroAssembler masm) {
  68         assert AMD64.rcx.equals(length.getRegister());
  69         masm.leaq(AMD64.rdi, pointer.toAddress());
  70         masm.xorq(AMD64.rax, AMD64.rax);
  71         masm.repStosb();
  72     }
  73 }