4 digit number

This is a discussion on 4 digit number within the C# Programming forums, part of the General Programming Boards category; i want to fill an array with 4 digit numbers ie location1 = 0040 location2 = 0050 location3 = 1234 ...

  1. #1
    budding software engineer luigi40's Avatar
    Join Date
    Jun 2004
    Location
    South Coast UK
    Posts
    61

    4 digit number

    i want to fill an array with 4 digit numbers ie location1 = 0040
    location2 = 0050
    location3 = 1234
    and so on....


    at the moment i am doing it as my code shows

    Code:
    /* CPU with 16bit instruction - 8bit instruction followed by 8bit operand, four 
     * addressing modes: absolute, literal, indexed, relative                    */
    
    
    using System;
    
    namespace cpu16bit_sim
    {
    	
    	class cpu_16bit
    	{
    	const int MOVE = 00;
    	const int ADD  = 01;
    	const int SUB  = 02;
    	const int BRA  = 03;
    	const int CMP  = 04;
    	const int BEQ  = 05;
    	const int BNE  = 06;
    	const int EXG  = 07;
    	const int STOP = 15;
    
    /* instruction format:														  */
    /* 7 6 5 4 3 2 1 0															  */
    /* bits 1 and 0 = 2bit addressing mode										  */
    /*				  00 address mode = absolute								  */
    /*				  01 address mode = literal									  */
    /*				  10 address mode = indexed									  */
    /*			      11 address mode = relative								  */
    /* bit 2 = 1bit direction (source/operand)									  */
    /* bit 3 = not used															  */
    /* bit 4 to 7 4bit instruction code											  */
    
    
    		static void Main(string[] args)
    		{
    			int PC = 0;					// program counter 
    			int D0 = 0;					// data register
    			int A0 = 0;					// address register
    			int CCR = 0;				// condition code register
    			int MAR = 0;				// memory address register
    			int MBR = 0;				// memory buffer register
    			int IR = 0;					// instruction register
    			int operand = 0;			// 8bit operand from the IR
    			int source = 0;				// source operand
    			int destination = 0;		// destination value
    			int opcode = 0;				// 4bit opcode from IR
    			int amode = 0;				// 2bit addressing mode
    			int direction;				// 1bit data direction
    			int[] memory = new int[256];// 256 byte memory 
    			bool run = true;			// program flag
    			int init = 0;
    			
    			while(init != -1)
    			{	
    				int fill = 0; 
    				Console.Write("Please enter program one instruction at a");
    				Console.WriteLine(" time, type -1 to end");
    				Console.WriteLine("MOVE = 00");
    				Console.WriteLine("ADD  = 01");
    				Console.WriteLine("SUB  = 02");
    				Console.WriteLine("BRA  = 03");
    				Console.WriteLine("CMP  = 04");
    				Console.WriteLine("BEQ  = 05");
    				Console.WriteLine("BNE  = 06");
    				Console.WriteLine("EXG  = 07");
    				Console.WriteLine("STOP = 15");
    				memory[fill++] = Int32.Parse( Console.ReadLine() );
    				Console.WriteLine(" another instruction?");
    				init = Int32.Parse( Console.ReadLine() );
    			}
    
    			while(run)
    			{
    				MAR = PC;
    				PC += 1;  
    				MBR = memory[MAR]; // fetch next instruction
    				IR = MBR;
    				opcode = IR;
    				MAR = PC;
    				PC += 1;
    				MBR = memory[MAR]; // fetch operand
    				IR = MBR;
    				operand = IR;
    				amode = (opcode & 0x03); // extract the address mode bits
    				direction = (opcode & 0x04) >> 2; /* get data direction 
    												   * 0 = reg to mem
    												   * 1 = mem to reg     */
    				opcode = (opcode >> 0x04); // extract 4bit instruction code
    
    				// use the addressing mode to get the source operand
    				switch(amode)
    				{
    					case 0: {source = memory[operand]; break;}		// absolute
    					case 1: {source = operand; break;}				// literal
    					case 2: {source = memory[A0+operand]; break;}	// indexed
    					case 3: {source = memory[PC+operand]; break;}// PC relative
    				}
    				
    				// execute the instruction
    				switch(opcode)
    				{
    					case MOVE: 
    					{
    						if(direction==0) destination=D0; 
    							else D0 = source;
    								if(D0==0) CCR=1;
    							else CCR=0;
    						break;
    					}
    
    					case ADD: 
    					{
    						if(direction==0)
    						{
    							destination=D0+source;
    							if(destination==0) CCR=1; else CCR=0;}
    						else
    						{
    							D0=D0+source;
    							if(D0==0) CCR=1; else CCR=0;
    						}
    						break;
    					}
    
    					case SUB:
    					{
    						if(direction==0)
    						{
    							destination=D0-source;
    							if(destination==0) CCR=1; else CCR=0;
    						}
    						else
    						{
    							D0=D0-source;
    							if(D0==0) CCR=1; else CCR=0;
    						}
    						break;
    					} 
    
    					case BRA: 
    					{
    						if(amode==0) PC=operand;
    							if(amode==1) PC=PC+operand;
    						break;
    					}
    
    					case CMP:
    					{
    						MBR=D0-source;
    						if(MBR==0) CCR=1;
    							else CCR=0; 
    						break;
    					}
    
    					case BEQ: 
    					{
    						if(CCR==1){
    							if(amode==0) PC=operand;
    							if(amode==1) PC=PC+operand;
    						}break; 
    					}
    
    					case BNE: 
    					{
    						if(CCR!=1){
    							if(amode==0) PC=operand;
    							if(amode==1) PC=PC+operand;
    						}break;
    					}
    
    					case EXG: 
    					{
    						MBR=D0; D0=A0; A0=MBR; break;
    					}
    
    					case STOP:
    					{
    						run=false; break;
    					}
    
    				}// end switch(opcode)
    
    				// save result in memory if register to memory
    				if(direction==0)
    					switch(amode)
    					{
    
    						case 0: {memory[operand]=destination; break; //absolute
    						}
    						case 1: { break;							 //literal
    						}
    						case 2: {memory[A0+operand]=destination;     //indexed
    								  break;
    						}
    						case 3: {memory[PC+operand]=destination;	//PC relative 
    								  break; 
    						}
    					}
    
    			}// end while(run)
    
    		}// end main
    
    	}// end class
    
    }//end namespace
    however the 4 digit number is only correct when the leading digits dont equal zero, ie 1234 if i enter 0040 the leading zeros are stripped leaving 40 in array, how can i fill the array from a digit number entered by the user that has 2 leading zeros


    luigi

  2. #2
    Banned nickname_changed's Avatar
    Join Date
    Feb 2003
    Location
    Australia
    Posts
    986
    Eww that looks like C code! :P

    Anyway, I don't have the time to read all your code, but I believe your problem is in calling Int.Parse on Console.ReadLine(). The integer "0040" can be represented as "40" or "00000040", it's really the same thing. If you need to keep it as 0040, then perhaps consider storing it as an array of strings. Otherwise when outputting it there is a way to 'pad' output by adding extra zeros to the front if needed (this should help: http://idunno.org/displayBlog.aspx/2004071401).

    Post a smaller example that highlights your problem and I'll be happy to have a proper read.

Popular pages Recent additions subscribe to a feed

Similar Threads

  1. Number Guessing
    By blacknapalm in forum C Programming
    Replies: 2
    Last Post: 10-01-2008, 01:48 AM
  2. how to read a digit of a floating point number?????
    By spicy_centipede in forum C Programming
    Replies: 15
    Last Post: 07-14-2007, 11:43 AM
  3. Random number + guessing game trouble
    By Ravens'sWrath in forum C Programming
    Replies: 16
    Last Post: 05-08-2007, 03:33 AM
  4. outputs number digit by digit
    By Unregistered in forum C++ Programming
    Replies: 14
    Last Post: 05-17-2002, 04:43 PM
  5. Random Number problem in number guessing game...
    By -leech- in forum Windows Programming
    Replies: 8
    Last Post: 01-15-2002, 04:00 PM

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21