vcpu.java

用jAVA实现的一个CPU32位的指令代码

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;

public class Vcpu {
	private Memory mem;
	static long eip;

	public Vcpu(Memory mem, long eip) {
		this.mem = mem;
		Vcpu.eip = eip;
	}

	public Vcpu(Memory mem) {
		this.mem = mem;
		Vcpu.eip = Memory.CODEBASE;
	}

	public Vcpu() {
		
	}

	public void reset(Memory mem){
		Vcpu.eip = Memory.CODEBASE;
		this.mem=mem;
	}
	// loader .exe file
	public boolean loader(File exeFile) throws IOException {

		FileInputStream ins = new FileInputStream(exeFile);
		InputStreamReader in = new InputStreamReader(ins);
		BufferedReader bin = new BufferedReader(in);
		String tmp;
		long codeaddr = Memory.CODEBASE;
		while ((tmp = bin.readLine()) != null) {
			if (codeaddr < Memory.MAXADDR) {
				mem.loader(codeaddr++, tmp);
			} else {
				return false;
			}

		}
		mem.loader(codeaddr, "exit");
		return true;
	}
	//start cpu
	public void start(){
		String instruction;
		while(!(instruction=this.fetch()).equals("exit")){
//			System.out.println(instruction);
			this.execute(instruction);
		}
		System.out.println("Exit :)");
	}

	// fetch instruction
	public String fetch() {
		System.out.print("eip=0x"+Long.toHexString(Vcpu.eip)+" :");
		String instruction = mem.read(Vcpu.eip++);
		System.out.println(instruction);
		return instruction;
	}
	public void test(){
		
	}

	// decode instruction
	public OpType decode(String instruction) {
		String opstr = instruction.substring(instruction.length() - 3,
				instruction.length());
		// int opcodeINT = Integer.parseInt(opstr);
		// OpType opType;
		if (opstr.equals("000")) {
			return OpType.MOVL;
		} else if (opstr.equals("001")) {
			return OpType.ADDL;
		} else if (opstr.equals("010")) {
			return OpType.SUBL;
		} else if (opstr.equals("011")) {
			return OpType.MULL;
		} else if (opstr.equals("100")) {
			return OpType.PRINT;
		} else
			return null;
	}

	// execute instruction
	public void execute(String instruction) {
		OpType opcode = this.decode(instruction); // decode instruction
		OprandFlag flag = this.getFlag(instruction); // get flag of first
		String firstOprandStr = this.getFirstOprand(instruction, flag);
		Long secondOprandAddr = this.getSecondOprand(instruction);
		String secOprandStr;
		Long secondOprand;
		if (opcode != null) {
			switch (opcode) {
			case MOVL:
				this.mem.write(secondOprandAddr, firstOprandStr);
				break;
			case ADDL:
				secOprandStr = this.mem.read(secondOprandAddr);
				secondOprand = this.strDataToLong(secOprandStr);
				secondOprand += this.strDataToLong(firstOprandStr);

				this.mem.write(secondOprandAddr, this
						.LongDataToStr(secondOprand));
				break;
			case SUBL:
				secOprandStr = this.mem.read(secondOprandAddr);
				secondOprand = this.strDataToLong(secOprandStr);
				secondOprand = this.strDataToLong(firstOprandStr)-secondOprand;
				this.mem.write(secondOprandAddr, this
						.LongDataToStr(secondOprand));
				break;
			case MULL:
				secOprandStr = this.mem.read(secondOprandAddr);
				secondOprand = this.strDataToLong(secOprandStr);
				secondOprand *= this.strDataToLong(firstOprandStr);

				this.mem.write(secondOprandAddr, this
						.LongDataToStr(secondOprand));
				break;
			case PRINT:
				Long firstOprand = this.strDataToLong(firstOprandStr);
				System.out.println("Result:"+firstOprand);
				break;
			}
		}

	}

	// get the flag of first oprand
	public OprandFlag getFlag(String instruction) {
		char flag = instruction.charAt(instruction.length() - 4);
		if (flag == '0') {
			return OprandFlag.ID;
		} else if (flag == '1') {
			return OprandFlag.NUM;
		}
		return null;
	}

	// get first oprand
	public String getFirstOprand(String instruction, OprandFlag flag) {
		String firstOprand = instruction.substring(14, 28);
		if ((flag != null) && flag.equals(OprandFlag.ID)) {
			Long addr = this.strAddrToLong(firstOprand);
			return this.mem.read(addr);
		} else if ((flag != null) && flag.equals(OprandFlag.NUM)) {
			return firstOprand;
		}
		return null;

	}

	// get second oprand
	public Long getSecondOprand(String instruction) {
		String secondOprand = instruction.substring(0, 14);

		return this.strAddrToLong(secondOprand);
	}

	// translate String addr to long addr
	public Long strAddrToLong(String strAddr) {
		char[] addr = strAddr.toCharArray();
		char tmp;
		Long addrLong = 0L;
		int tag;
		int size = addr.length;
		for (int i = 0; i < size; i++) {
			tmp = addr[i];
			tag = size - 1 - i;
			if (tmp == '1') {
				addrLong += (long) Math.pow(2, tag);
			}
		}
		return addrLong;
	}

	// translate Data string to long;
	public Long strDataToLong(String strData) {
		char[] data = strData.toCharArray();
		int leng = data.length;
		if (data[0] == '0') {
			return this.strAddrToLong(strData);
		} else {
			Long tmp = (long) Math.pow(2, leng) - this.strAddrToLong(strData);
			return 0 - tmp;
		}
	}

	// translate Data long to string
	public String LongDataToStr(Long data) {
		String strData = Long.toBinaryString(data);
		String subStr=strData;
		if(strData.length()<32){
			subStr=strData;
			int rest=32-strData.length();
			for(int i=0;i<rest;i++){
				subStr="0"+strData;
			}
		}else if(strData.length()>32){
			subStr=strData.substring(32, 64);
		}
		return subStr;
	}

	public Memory getMem() {
		return mem;
	}

	public void setMem(Memory mem) {
		this.mem = mem;
	}

	public long getEip() {
		return eip;
	}

}