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package svm;
import java.util.concurrent.TimeUnit;
public class ExecuteVM {
public static final int CODESIZE = 1000 ;
public static final int MEMSIZE = 1000 ; //10000;
private AssemblyClass[] code;
private int[] memory = new int[MEMSIZE];
private int ip = 0; // instruction pointer
private int sp = MEMSIZE-1 ; // stack pointer
private int al = MEMSIZE-2 ; // access link
private int fp = MEMSIZE-1 ; // frame pointer
private int ra; // return address
private int a0; // the register for values of expressions
private int t1; // temporary register
private int t2; // additional temporary register, just in case
public ExecuteVM(AssemblyClass[] _code) {
code = _code ;
}
public void StampaMem(int _j){
System.out.print(_j + ": " + code[ip].getCode()) ;
for (int i = MEMSIZE-1; i > sp ; i--){
System.out.print("\t" + memory[i]) ;
}
System.out.println(" ----- " + "SP = " + sp + ", FP = " + fp + ", AL = " + al + ", RA = " + ra + ", A0 = " + a0 + ", T1 = " + t1 ) ;
}
public int read(String _strg) {
int tmp ;
switch (_strg) {
case "IP":
tmp = ip ;
break ;
case "SP":
tmp = sp ;
break ;
case "AL":
tmp = al ;
break ;
case "FP":
tmp = fp ;
break ;
case "RA":
tmp = ra ;
break ;
case "A0":
tmp = a0 ;
break ;
case "T1":
tmp = t1 ;
break ;
case "T2":
tmp = t2 ;
break ;
default :
tmp = -99999 ; // error value
break ;
}
return tmp ;
}
public void update(String _strg, int _val) {
switch (_strg) {
case "IP":
ip = _val ;
break ;
case "SP":
sp = _val ;
break ;
case "AL":
al = _val ;
break ;
case "FP":
fp = _val ;
break ;
case "RA":
ra = _val ;
break ;
case "A0":
a0 = _val;
break ;
case "T1":
t1 = _val ;
break ;
case "T2":
t2 = _val ;
break ;
default :
// error value
break ;
}
}
public void cpu() {
int j = 0 ;
while ( true ) {
// try {
// TimeUnit.SECONDS.sleep(1);
// } catch (InterruptedException e) {
// // TODO Auto-generated catch block
// e.printStackTrace();
// }
StampaMem(j) ; j=j+1 ;
AssemblyClass bytecode = code[ip] ; // fetch
int tmp ;
int address;
switch ( bytecode.getCode() ) {
case SVMParser.PUSH:
push(Integer.parseInt(bytecode.getArg1())) ;
ip = ip+1 ;
break;
case SVMParser.PUSHR:
push(read(bytecode.getArg1()));
ip = ip+1 ;
break ;
case SVMParser.POP:
pop();
ip = ip+1 ;
break;
case SVMParser.LOAD:
tmp = read(bytecode.getArg3()) + Integer.parseInt(bytecode.getArg2()) ;
if ((tmp < 0) || (tmp >= MEMSIZE)) {
System.out.println("\nError: Null pointer exception1");
return;
} else {
memory[tmp] = read(bytecode.getArg1()) ;
ip = ip+1 ;
break;
}
case SVMParser.STOREI:
update(bytecode.getArg1(), Integer.parseInt(bytecode.getArg2())) ;
ip = ip+1 ;
break;
case SVMParser.STORE:
tmp = read(bytecode.getArg3()) + Integer.parseInt(bytecode.getArg2());
if ((tmp < 0) || (tmp >= MEMSIZE)) {
System.out.println("\nError: Null pointer exception2");
return;
} else {
update(bytecode.getArg1(), memory[tmp]);
ip = ip+1 ;
break;
}
case SVMParser.MOVE:
update(bytecode.getArg2(), read(bytecode.getArg1())) ;
ip = ip+1 ;
break;
case SVMParser.ADD:
push(read(bytecode.getArg1()) + read(bytecode.getArg2())) ;
ip = ip+1 ;
break;
case SVMParser.ADDI:
update(bytecode.getArg1(), read(bytecode.getArg1()) + Integer.parseInt(bytecode.getArg2()) );
ip = ip+1 ;
break;
case SVMParser.SUB:
push(read(bytecode.getArg1()) - read(bytecode.getArg2()));
ip = ip+1 ;
break;
case SVMParser.SUBI:
update(bytecode.getArg1(), read(bytecode.getArg1()) - Integer.parseInt(bytecode.getArg2()) );
ip = ip+1 ;
break;
case SVMParser.MUL:
push(read(bytecode.getArg1()) * read(bytecode.getArg2()));
ip = ip+1 ;
break;
case SVMParser.MULI:
update(bytecode.getArg1(), read(bytecode.getArg1()) * Integer.parseInt(bytecode.getArg2()) ) ;
ip = ip+1 ;
break;
case SVMParser.DIV:
push(read(bytecode.getArg1()) / read(bytecode.getArg2()));
ip = ip+1 ;
break;
case SVMParser.DIVI:
update(bytecode.getArg1(), read(bytecode.getArg1()) / Integer.parseInt(bytecode.getArg2()) );
ip = ip+1 ;
break;
case SVMParser.POPR : //
update(bytecode.getArg1(), memory[sp+1]);
pop() ;
ip = ip+1 ;
break;
case SVMParser.BRANCH:
address = ip + 1;
ip = code[address].getCode() ;
break;
case SVMParser.BRANCHEQ : //
if (read(bytecode.getArg1()) == read(bytecode.getArg2())){
address = ip+1;
ip = code[address].getCode() ;
} else ip = ip+2 ;
break;
case SVMParser.BRANCHLESSEQ :
if (read(bytecode.getArg1()) <= read(bytecode.getArg2())){
address = ip+1;
ip = code[address].getCode() ;
} else ip = ip+2 ;
break;
case SVMParser.JUMPSUB :
ra = ip+1 ;
address = ip ;
ip = Integer.parseInt(code[address].getArg1()) ;
break;
case SVMParser.RETURNSUB:
ip = read(bytecode.getArg1()) ;
break;
case SVMParser.HALT : //to print the result
System.out.println("\nResult: " + a0 + "\n");
return;
}
}
}
private int pop() {
sp = sp+1 ;
return memory[sp] ;
}
private void push(int v) {
memory[sp] = v;
sp = sp-1 ;
}
}
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