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 * permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this list of
 * conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of
 * conditions and the following disclaimer in the documentation and/or other materials provided
 * with the distribution.
 *
 * 3. Neither the name of the copyright holder nor the names of its contributors may be used to
 * endorse or promote products derived from this software without specific prior written
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS
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package com.oracle.truffle.llvm.runtime.nodes.asm;

import com.oracle.truffle.api.CompilerDirectives;
import com.oracle.truffle.api.Truffle;
import com.oracle.truffle.api.dsl.Specialization;
import com.oracle.truffle.api.frame.VirtualFrame;
import com.oracle.truffle.api.nodes.LoopNode;
import com.oracle.truffle.api.nodes.RepeatingNode;
import com.oracle.truffle.api.nodes.UnexpectedResultException;
import com.oracle.truffle.llvm.runtime.nodes.asm.support.LLVMAMD64WriteValueNode;
import com.oracle.truffle.llvm.runtime.nodes.api.LLVMExpressionNode;
import com.oracle.truffle.llvm.runtime.nodes.api.LLVMNode;
import com.oracle.truffle.llvm.runtime.nodes.api.LLVMStatementNode;

public abstract class LLVMAMD64RepNode extends LLVMStatementNode {

    @Child private LoopNode loop;

    public LLVMAMD64RepNode(LLVMAMD64WriteValueNode writeRCX, LLVMExpressionNode rcx, LLVMStatementNode body) {
        this.loop = Truffle.getRuntime().createLoopNode(new LLVMAMD64RepLoopNode(writeRCX, rcx, body));
    }

    @Specialization
    public void doRep(VirtualFrame frame) {
        loop.execute(frame);
    }

    private static class LLVMAMD64RepLoopNode extends LLVMNode implements RepeatingNode {
        @Child private LLVMAMD64WriteValueNode writeRCX;
        @Child private LLVMExpressionNode rcx;
        @Child private LLVMStatementNode body;

        LLVMAMD64RepLoopNode(LLVMAMD64WriteValueNode writeRCX, LLVMExpressionNode rcx, LLVMStatementNode body) {
            this.writeRCX = writeRCX;
            this.rcx = rcx;
            this.body = body;
        }

        @Override
        public boolean executeRepeating(VirtualFrame frame) {
            try {
                long rcxValue = rcx.executeI64(frame);
                if (rcxValue == 0) {
                    return false;
                } else {
                    body.execute(frame);
                    writeRCX.execute(frame, rcxValue - 1);
                    return true;
                }
            } catch (UnexpectedResultException e) {
                CompilerDirectives.transferToInterpreter();
                throw new RuntimeException(e);
            }
        }
    }
}