implemning assembly interpreter in Java

[halona]

I have this code in assembly

1024=15; //memory location
1025=24; //memory location
1023=34; //memory location
SUB R1,R1,0
LD R1,R1,1024
SUB R2,R2,0
LD R2,R2,1025
SUB R3,R3,0
LD R3,R3,1023
MUL R1,R2,0
DIV R1,R3,0


and I want to write an interpreter for it in Java..

I started in the code .. determine the syntax structure.. but couldn't write the code in Jave .. where and what..

so .. I need some one to guide me to what should I do .. to finish this interpreter.

this is what I wrote so far

grammar Expr;

@header {
import java.util.HashMap;
}

@members {
/** Map variable name to Integer object holding value */
int[] regi=new int[32];
int[] mem=new int[65536];
int counter=0;




HashMap memory = new HashMap();
int firstreg;
int regvalue;
int intvalue;
int	regValue(String x)	{
	int reg;

	if(x.compareTo(new String("R0")) == 0)
		reg = 0;
	else if (x.compareTo(new String("R1")) == 0)
		reg = 1;
	else if (x.compareTo(new String("R2")) == 0)
		reg = 2;
	else if (x.compareTo(new String("R3")) == 0)
		reg = 3;
	else if (x.compareTo(new String("R4")) == 0)
		reg = 4;
	else if (x.compareTo(new String("R5")) == 0)
		reg = 5;
	else if (x.compareTo(new String("R6")) == 0)
		reg = 6;
	else if (x.compareTo(new String("R7")) == 0)
		reg = 7;
	else if (x.compareTo(new String("R8")) == 0)
		reg = 8;
	else if (x.compareTo(new String("R9")) == 0)
		reg = 9;
	else if (x.compareTo(new String("R10")) == 0)
		reg = 10;
	else if (x.compareTo(new String("R11")) == 0)
		reg = 11;
	else if (x.compareTo(new String("R12")) == 0)
		reg = 12;
	else if (x.compareTo(new String("R13")) == 0)
		reg = 13;
	else if (x.compareTo(new String("R14")) == 0)
		reg = 14;
	else if (x.compareTo(new String("R15")) == 0)
		reg = 15;
	else if (x.compareTo(new String("R16")) == 0)
		reg = 16;
	else if (x.compareTo(new String("R17")) == 0)
		reg = 17;
	else if (x.compareTo(new String("R18")) == 0)
		reg = 18;
	else if (x.compareTo(new String("R19")) == 0)
		reg = 19;
	else if (x.compareTo(new String("R20")) == 0)
		reg = 20;
	else if (x.compareTo(new String("R21")) == 0)
		reg = 21;
	else if (x.compareTo(new String("R22")) == 0)
		reg = 22;
	else if (x.compareTo(new String("R23")) == 0)
		reg = 23;
	else if (x.compareTo(new String("R24")) == 0)
		reg = 24;
	else if (x.compareTo(new String("R25")) == 0)
		reg = 25;
	else if (x.compareTo(new String("R26")) == 0)
		reg = 26;
	else if (x.compareTo(new String("R27")) == 0)
		reg = 27;
	else if (x.compareTo(new String("R28")) == 0)
		reg = 28;
	else if (x.compareTo(new String("R29")) == 0)
		reg = 29;
	else if (x.compareTo(new String("R30")) == 0)
		reg = 30;
	else if (x.compareTo(new String("R31")) == 0)
		reg = 31;
	else reg = -1;
	return reg;
}
}

prog:   stat+ ;
                
stat:   expr NEWLINE {System.out.println($expr.value);}
    |   ID '=' expr NEWLINE
        {memory.put($ID.text, new Integer($expr.value));}
    |   NEWLINE
    | LD REG COMMA regInExpr {System.out.println($LD.text + " " + regValue(new String($REG.text))+ " " + regvalue + " " + intvalue); }
    | DIV REG COMMA regInExpr {System.out.println($DIV.text + " " + regValue(new String($REG.text))+ " " + regvalue + " " + intvalue); } 
   | SUB REG COMMA regInExpr {System.out.println($SUB.text + " " + regValue(new String($REG.text))+ " " + regvalue + " " + intvalue); }
   | MUL REG COMMA regInExpr {System.out.println($MUL.text + " " + regValue(new String($REG.text))+ " " + regvalue + " " + intvalue); }
   | ST REG COMMA regInExpr {System.out.println($ST.text + " " + regValue(new String($REG.text))+ " " + regvalue + " " + intvalue); }
    ;
expr returns [int value]
    :   e=multExpr {$value = $e.value;}
        (   MUL e=multExpr {$value = $e.value;}
        |   SUB e=multExpr {$value -= $e.value;}
        |   DIV  e=multExpr {$value = $e.value;}
        |   LD  e=multExpr {$value += $e.value;}
        |   ST  e=multExpr {$value = $e.value;}  
        )*
    ;

regInExpr : REG COMMA INT { 
		if (counter==0)
		{mem [1024]=15;
		mem[1025]=24;
		mem[1023]=34;
		regi[0]=0;
		regi[1]=1;
		regi[2]=2;
		regi[3]=3;
		regi[4]=4;
		counter +=counter;
		regvalue = regValue(new String($REG.text));intvalue =   Integer.parseInt($INT.text);
		//System.out.println(mem[1024],mem[1025],mem[1023]);
		 }
		else

regvalue = regValue(new String($REG.text));intvalue =   Integer.parseInt($INT.text); };

multExpr returns [int value]
    :   e=atom {$value = $e.value;} ('*' e=atom {$value *= $e.value;})*
    ; 

atom returns [int value]
    :   INT {$value = Integer.parseInt($INT.text);}
    |   ID
        {
        Integer v = (Integer)memory.get($ID.text);
        if ( v!=null ) $value = v.intValue();
        else System.err.println("undefined variable "+$ID.text);
        }
    |   '(' expr ')' {$value = $expr.value;}
    ;

COMMA : ',';
LD    : 'L''D';
MUL   :'M''U''L'; 
DIV   :'D''I''V';
SUB   : 'S''U''B';
ST    :  'S''T';
REG   : 'R'('0'|'1'|'2') ('0'..'9') | 'R''3' ('0'|'1'|'2') | 'R'('0'|'1'|'2'|'3'|'4'|'5'|'6'|'7'|'8'|'9');
ID    :   ('a'..'z'|'A'..'Z')+ ;
INT   :   '0'..'9'+ ;
NEWLINE:'\r'? '\n' ;
WS  :   (' '|'\t')+ {skip();} ;

I am using ANTLR with this..
any one know please help me

thank u

[MeTh0Dz]

You are going about this entirely the wrong way. And from the looks of it you don't have the experience or knowledge required to write an assembly interpreter.

[halona]

You are going about this entirely the wrong way. And from the looks of it you don't have the experience or knowledge required to write an assembly interpreter.

yes I am..

I don't know what should I do.. I need larde help and guide as well

[WingedPanther]

Well, you'll need a memory model, variables to store registers, a parser, and logic to implement each possible statement correctly. There's probably a half dozen other things that I'm missing. That's just the high-level view. You can't just start coding, for something this big.

[halona]

Well, you'll need a memory model, variables to store registers, a parser, and logic to implement each possible statement correctly. There's probably a half dozen other things that I'm missing. That's just the high-level view. You can't just start coding, for something this big.

well..
for the memorey and the registers I have created an array to hold the value
with their sizes.

int[] regi=new int[32];
int[] mem=new int[65536];

iam not going to create the full compiler for the language..
it is just for the following code

1024=15; //memory location
1025=24; //memory location
1023=34; //memory location
SUB R1,R1,0
LD R1,R1,1024
SUB R2,R2,0
LD R2,R2,1025
SUB R3,R3,0
LD R3,R3,1023
MUL R1,R2,0
DIV R1,R3,0