run.java

//
// run.java
// Compile: javac run.java
//          env LC_ALL=en javac run.java		mac
//          javac -J-Dfile.encoding=UTF-8 run.java	mac
// Run: java run [file name]			-> run mode
//      java run -d [file name]			-> disassemble mode
//
 
/*
usage: 7run [-p] [-d|-v/-s] cmd [args ...]
-p: PDP-11 mode
-8: 8086/V6 mode
-d: disassemble mode (not run)
-m: verbose mode with memory dump
-v: verbose mode (output syscall and disassemble)
-s: syscall mode (output syscall)
*/

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;

class gv
{
	// GlobalVariable

	// .text + .data = memory area
	public static byte[] mem = new byte[1024];

	// .text area size 4 bytes
	public static int t_size;

	// .data area size 4 bytes
	public static int d_size;
}
 
public class run {

	// main
      public static void main(String[] argv) {
        
		System.out.println("binary file read program for Java");

		if (argv.length == 1){
			// run mode
			System.out.println("run mode");
			// read binary file
			fileRead(argv[0]);
			run_prog();
		} else if (argv.length == 2){
			String s=argv[0];
			if ( s.equals("-d")){
				// disassemble mode
				System.out.println("disassemble mode");
				// read binary file
				fileRead(argv[1]);
				disassemble();
			}else{
				System.out.println("no such switch");
				System.exit(1);
			}
		} else {
			System.out.println("usage: java run [-d] [file name]");
			System.exit(1);
		}

		System.exit(0);

	}
 
	// fileRead
	private static void fileRead( String inFile ) {
        
		// 読み込むファイルの名前
		//String inputFileName = "a0.out";
		String inputFileName = inFile ;
        	// ファイルオブジェクト生成
        	File inputFile = new File(inputFileName);
		
		System.out.println("Read File: " + inFile);
		
		try {
          	// 入力ストリームの生成
          	FileInputStream fis = new FileInputStream(inputFile);
          	BufferedInputStream bis = new BufferedInputStream(fis);
          	// ヘッダー部のバイト配列
          	byte[] header = new byte[16];
			// 2バイト分のデータ
			short w;
			// .text & .data area int:4bytes
			//int t_size, d_size;
			// 入力ストリームからの読み込み（ファイルの読み込み）
			int len = bis.read(header);
 
			// 読み込んだデータを16進形式で表示
          	String hex;
          	for ( int i = 0; i < len; i++ ) {
            	hex = String.format("%1$x ", header[i]);
            	hex = hex.length() == 2 ? "0" + hex : hex;
            	System.out.print(hex + " ");
          	}
          	System.out.println();
          
			hex = String.format("%1$x ", header[2]);
			// .text area size
			w = (short) ( header[2] | ( header[3] << 8 ) );
			gv.t_size = (int) w;
			// .data area size
			w = (short) ( header[4] | ( header[5] << 8 ) );
			gv.d_size = (int) w;
			//System.out.println(" t_size: " + gv.t_size + " d_size: " + gv.d_size);
			System.out.printf(" t_size: 0x%02x  d_size: 0x%02x \n", gv.t_size, gv.d_size);

			//len = bis.read(mem,0,(t_size+d_size));
			len = bis.read(gv.mem,0,(gv.t_size + gv.d_size));
			
			if( len != gv.t_size + gv.d_size ) {
				System.out.println("read size error !");
			}
			
			// 後始末
			bis.close();
		// エラーがあった場合は、スタックトレースを出力
		} catch(Exception e) {
			e.printStackTrace();
		}
	
	}
	
	// read 8 bits
	private static byte read8(int i){
	
		//System.out.println("read8");
		return gv.mem[i] ;
	}
	// read 16 bits
	private static short read16(int i){
		
		//System.out.println("read16");
		return (short) ( gv.mem[i] | ( gv.mem[i+1] << 8 ) ) ;
	}
	
	// run program
	private static void run_prog(){

		
		System.out.println("run start");

		
	}
	
	// disassemble
	private static void disassemble(){

		// 8 bits variable
		byte  b0,b1,b2;
		// 16 bits variable
		short w0,w1,w2;
		
		System.out.println("disassemble start");
		
		for (int i = 0; i < gv.t_size; i++) {
			b0 = read8(i);
			switch (b0){
			case (byte) 0xb8 :
				// mov ax
				w0 = read16(i+1) ;
				System.out.printf("%04x: %02x%02x%02x \t mov ax, %04x \n",i,read8(i),read8(i+1),read8(i+2),w0);
				i += 2;
				break;
			case (byte) 0xbb :
				// mov bx
				w0 = read16(i+1) ;
				System.out.printf("%04x: %02x%02x%02x \t mov bx, %04x \n",i,read8(i),read8(i+1),read8(i+2),w0);
				i += 2;
				break;
			case (byte) 0xc7 :
				b1 = read8(i+1);
				switch (b1){
				case (byte) 0x07 :
					// mov (bx)
					w0 = read16(i+2) ;
					System.out.printf("%04x: %02x%02x%02x%02x \t mov [bx], %04x \n",i,read8(i),read8(i+1),read8(i+2),read8(i+3),w0);
					i += 3;
					break;
				default :
					System.out.printf("%02x \t ; undefined %04x \n",b0,b0);
					break;
				}
				break;
			case (byte) 0xcd :
				// int
				b1 = read8(i+1);
				switch (b1){
				case (byte) 0x07 :
					// int 7
					System.out.printf("%04x: %02x%02x \t int %x \n",i,read8(i),read8(i+1),read8(i+1));
					i += 2;
					b2 = read8(i);
					switch (b2){
					case (byte) 0x01 :
						// sys exit 1
						System.out.printf("%04x: %02x \t ; sys exit \n",i,b2);
						//i += 1;
						break;
					case (byte) 0x04 :
						// sys write 4
						System.out.printf("%04x: %02x \t ; sys write \n",i,b2);
						i += 1;
						w0 = read16(i) ;
						System.out.printf("%04x: %02x%02x \t ; arg, %04x \n",i,read8(i),read8(i+1),w0);
						i += 2;
						w0 = read16(i) ;
						System.out.printf("%04x: %02x%02x \t ; arg, %04x \n",i,read8(i),read8(i+1),w0);
						i += 1;
						break;
					default :
						System.out.printf("%04x: %02x \t ; undefined %04x \n",i,b0,b0);
						break;
					}
					break;
				default :
					System.out.printf("%04x: %02x \t ; undefined %04x \n",i,b0,b0);
					break;
				}
					//printf("%04x: %02x%02x \t int %x \n",i,read8(i),read8(i+1),read8(i+1));
					//i += 1;
					break;
			case (byte) 0x10 :
				System.out.printf("%04x: %02x%02x \t ; arg \n",i,read8(i),read8(i+1));
				i += 1;
				break;
			case (byte) 0x06 :
				System.out.printf("%04x: %02x%02x \t ; arg \n",i,read8(i),read8(i+1));
				i += 1;
				break;
			case (byte) 0x00 :
				System.out.printf("%04x: %02x \t (undefined) \n",i,b0);
				break;
			default:
				System.out.printf("%04x: %02x \t ; arg def %04x \n",i,b0,b0);
				break;
			}
			
		}

	}

}