操作系统模拟虚拟存储器的地址变换过程

设计用于模拟快表、页表、地址变换所用的寄存器的数据结构；
编制页表的初始信息文件，举例说明文件中具有的信息：共有5块，每块的状态、在内存和外存的起始地址等。
编程实现虚拟存储器地址变换算法程序，动态输入所要访问的逻辑地址，变换过程文字描述以及变换后的物理地址；
测试：输入有效、无效地址，测试程序的正确性和错误处理能力。
实验结果：
虚拟地址变换程序提供逻辑地址输入界面，形象地表示出变换成物理地址的过程与最后变换成的物理地址。
快表的地址变换原理

需要输入一个数 地址变换算法计算出所在的页号 先访问快表 找不到再访问页表 根据表里的块号 计算出物理地址 块号*块大小+偏移量

页表结构
PageTableManager

package AddressTransformation;

import java.util.HashMap;
import java.util.Map;

public class PageTableManager {
    private Map<Integer, PageTableEntry> pageTable = new HashMap<>();

    public static class PageTableEntry {
        private int frameNumber;
        private boolean present;
        private int pageNumber;

        public PageTableEntry(int pageNumber, int frameNumber, boolean present) {
            this.pageNumber = pageNumber;
            this.frameNumber = frameNumber;
            this.present = present;
        }

        public int getFrameNumber() {
            return frameNumber;
        }

        public boolean isPresent() {
            return present;
        }

        public int getPageNumber() {
            return pageNumber;
        }
    }

    public void setEntry(int pageNumber, int frameNumber, boolean present) {
        pageTable.put(pageNumber, new PageTableEntry(pageNumber, frameNumber, present));
    }

    public PageTableEntry getEntry(int pageNumber) {
        return pageTable.get(pageNumber);
    }
}

快表结构

TLBManager

package AddressTransformation;

import java.util.HashMap;
import java.util.Map;

public class TLBManager {
    private Map<Integer, TLBEntry> tlb = new HashMap<>();

    public static class TLBEntry {
        private int virtualPageNumber;
        private int physicalFrameNumber;

        public TLBEntry(int virtualPageNumber, int physicalFrameNumber) {
            this.virtualPageNumber = virtualPageNumber;
            this.physicalFrameNumber = physicalFrameNumber;
        }

        public int getVirtualPageNumber() {
            return virtualPageNumber;
        }

        public int getPhysicalFrameNumber() {
            return physicalFrameNumber;
        }
    }

    public TLBEntry lookup(int virtualPageNumber) {
        return tlb.get(virtualPageNumber);
    }

    public void update(int virtualPageNumber, int physicalFrameNumber) {
        tlb.put(virtualPageNumber, new TLBEntry(virtualPageNumber, physicalFrameNumber));
    }
}

地址变换算法
AddressTransformation.java

package AddressTransformation;

public class AddressTransformation {
        private PageTableManager pageTableManager;
        private TLBManager tlbManager;
        private int pageSize;

        public AddressTransformation(int pageSize) {
            this.pageSize = pageSize;
            this.pageTableManager = new PageTableManager();
            this.tlbManager = new TLBManager();
        }

        public String addressTranslation(int virtualAddress) {
            int pageNumber = virtualAddress / pageSize;
            int offset = virtualAddress % pageSize;

            TLBManager.TLBEntry tlbEntry = tlbManager.lookup(pageNumber);
            if (tlbEntry != null) {
                int frameNumber = tlbEntry.getPhysicalFrameNumber();
                return "TLB 命中。物理地址：" + (frameNumber * pageSize + offset) + "（帧号：" + frameNumber + "，偏移量：" + offset + "）";
            } else {
                PageTableManager.PageTableEntry ptEntry = pageTableManager.getEntry(pageNumber);
                if (ptEntry != null && ptEntry.isPresent()) {
                    int frameNumber = ptEntry.getFrameNumber();
                    tlbManager.update(pageNumber, frameNumber);
                    return "TLB 未命中。物理地址：" + (frameNumber * pageSize + offset) + "（帧号：" + frameNumber + "，偏移量：" + offset + "）";
                } else {
                    return "页面错误。页号 " + pageNumber + " 不在内存中。";
                }
            }
        }

        public void setPageTableEntry(int pageNumber, int frameNumber, boolean present) {
            pageTableManager.setEntry(pageNumber, frameNumber, present);
        }

        public void setTLBEntry(int virtualPageNumber, int physicalFrameNumber) {
            tlbManager.update(virtualPageNumber, physicalFrameNumber);
        }

}

测试类
Test.java

package AddressTransformation;
import java.util.Scanner;

public class Test {
    public static void main(String[] args) {
        AddressTransformation simulator = new AddressTransformation(1024); // 假设页面大小为1024

        // 初始化页表和TLB
        simulator.setPageTableEntry(1, 0, true);
        simulator.setPageTableEntry(2, 1, true);
        simulator.setPageTableEntry(3, 2, true);
        simulator.setPageTableEntry(4, 3, true);
        simulator.setPageTableEntry(5, 4, true);

        simulator.setTLBEntry(1, 0);
        simulator.setTLBEntry(2, 1);

        Scanner scanner = new Scanner(System.in);
        System.out.println("输入虚拟地址（或输入-1退出）：");
        while (true) {
            int virtualAddress = scanner.nextInt();
            if (virtualAddress == -1) {
                break;
            }
            String result = simulator.addressTranslation(virtualAddress);
            System.out.println(result);
            System.out.println("输入虚拟地址（或输入-1退出）：");
        }
        scanner.close();
    }
}

测试结果