/*
	Copyright (c) 1996-1997 Swiss Federal Institute of Technology, 
	Computer Engineering and Networks Laboratory. All rights reserved.

	Written by George Fankhauser <gfa@acm.org>. For more documentation
	please visit http://www.tik.ee.ethz.ch/~gfa.

	
	File:                  $Source: /private/proj/topsy/gfa/MipsSimulator/RCS/KernelLoader.version_for_applet.java,v $
 	Author(s):             G. Fankhauser
 	Affiliation:           ETH Zuerich, TIK
 	Version:               $Revision: 1.1 $
 	Creation Date:         December 1996
 	Last Date of Change:   $Date: 98/04/13 16:58:33 $      by: $Author: gfa $
	
	
	$Log:	KernelLoader.version_for_applet.java,v $
Revision 1.1  98/04/13  16:58:33  gfa
Initial revision

# Revision 1.2  1997/04/06  12:59:41  gfa
# adapted for the applet interface, processor runs also as a thread...
#
# Revision 1.1  1997/02/04  10:42:01  topsy
# Initial revision
#
*/

import java.lang.*;
import java.io.*;
import Memory;
import Processor;

public class KernelLoader extends Object {
	
	static final byte nullChar = (byte)'0';
	static final byte capAChar = (byte)'A';

	KernelLoader(RandomAccessFile f, Memory m, Processor p, DataInputStream is) throws Exception
	{		
	/*  s-record loader, supports only 32bit addresses and transfer:
		S3   Data record with 32 bit load address                            
		S7   Termination record with 32 bit transfer address

		Stnnaaaaaaaa[dddd...dddd]cc

		t record type field (0,1,2,3,6,7,8,9). 		
		nn record length field, number of bytes in record excluding record type 
		and record length. 
		a...a load address field, can be 16, 24 or 32 bit address for data to 
		be loaded. 
		d...d data field, actual data to load, each byte is encoded in 2 
		characters. 
		cc checksum field, 1's complement of the sum of all bytes in the record
		length, load address and data fields 
	*/
		try {
			int i;
			while (true) {
				String s = is.readLine(); 
				if (s.charAt(0) != 'S') throw new KernelLoaderException();
				if (s.charAt(1) == '3') {
					int count = (int)readHexByte(s, 2);
					int start = readHexInt(s, 4);
					int pc = start-0x80000000; // translate by hand
					for (i = 12; i < ((count-5)*2 + 12); i+=2) {
						m.writeByte(pc++, readHexByte(s, i));
						// disassemble program
						if (false) {
							if (pc % 4 == 0) {	
								Instruction n = 
											new Instruction(m.readInt(pc-4));	
								n.decode();
								System.out.print
									(Integer.toHexString(pc-4) + "  \t");
								System.out.println(n.disassemble());
							}		
						}
						else {
							animateLoading(pc);
						}
					}
				}
				else if (s.charAt(1) == '7') {
					int count = (int)(readHexByte(s, 2));
					int start = readHexInt(s, 4);
					p.rom.insertDefaultCode(start);
				}
				// ignore other Sx's
			}
		}
		catch (NullPointerException exception) { 
		}
		catch (EOFException exception) {
			System.out.write('\b');
		}
	}
	
	byte hexDigit(byte b) {
		if ((b >= nullChar) && (b < (nullChar+10))) {
			return (byte)(b - nullChar);
		}
		else if ((b >= capAChar) && (b < (capAChar+6))) {
			return (byte)(b - capAChar + 10);
		}
		else {
			return (byte)0;
		}	
	}
		
	byte readHexByte(String s, int i) {
		byte b0 = (byte)s.charAt(i);
		byte b1 = (byte)s.charAt(i+1);	
		return (byte)(16*hexDigit(b0) + hexDigit(b1));
	}
		
	int readHexInt(String s, int i) {	
		int a = (int)readHexByte(s, i);
		int b = (int)readHexByte(s, i+2);
		int c = (int)readHexByte(s, i+4);
		int d = (int)readHexByte(s, i+6);
		
		a = a << 24;
		b = (b << 16) & 0x00ff0000;
		c = (c << 8) & 0x0000ff00;
		d = d & 0x000000ff;
		return (a|b|c|d);
	}
		
	void animateLoading(int i) {
		//int N = 4*128;
		int N = 4*1024;
		
		/* old version animation in sun eprom style
		System.out.print("\b");
		if (i%N == 0) System.out.write('-');
		if (i%N == N/4) System.out.write('\\');
		if (i%N == N/2) System.out.write('|');
		if (i%N == (N/4)*3) System.out.write('/');
		*/
		/* new version is applet compatible */
		if (i%N == 0) {
		    SimulatorApplet.out.print(".");
		    SimulatorApplet.out.flush();
		}
	}
}


class KernelLoaderException extends Exception {	
	KernelLoaderException() {		
	}
}