I'm assuming its a simple formating issue, however i cannt see it at the moment as I have been staring at this code for a few dozen hours now. The intended ouput should show a string i.e. "add" or "or" instead of "null". The string in question is functionR.
all input will be taken as helpful input.
package src;
import java.util.Arrays;
import java.util.Scanner;
public class Decoder {
public static int Instructions [] = new int [] {0x022Da822, 0x8ef30018, 0x12a70004,
0x02689820, 0xad930018, 0x02697824, 0xAD8ffff4,
0x018c6020, 0x02a4a825, 0x158ffff6, 0x8E59fff0};
public int address = 0x7A060;
public int startaddress=0x7A060;
public int opcode;
public int srcReg1;
public int srcReg2;
public int destreg;
public int sdReg;
public static int functcode;
public short offset;
int offaddress;
public int masks1 = 0x03e00000;
public int masks2dst= 0x001f0000;
public int masksDst = 0x0000f800;
public static int maskFunc = 0x0000003f;
public static int maskOpCode = 0xfc000000;
public int maskSDIform = 0x001f0000;
public int maskoffset=0x0000ffff;
Scanner input = new Scanner(System.in);
public static int opcodetest = (Instructions[3]&maskOpCode)>>>26;
public static int test = Instructions[0]>>>26;
public int srcReg1test = (Instructions[1]&masks1)>>>21;
public static int functcode0=(Instructions[0]&maskFunc);
public static int functcode3=(Instructions[3]&maskFunc);
public static int functcode5=(Instructions[5]&maskFunc);
public static int functcode7=(Instructions[7]&maskFunc);
public static int functcode8=(Instructions[8]&maskFunc);
public String functionR;
//not really a get method, just testing implementation of variables
/*
public int testingopcode()
{
for(int x=0;x<Instructions.length;x++)
{
opcode = Instructions[x]>>>26;
//Just a little formal check
System.out.println("Instructions in binary:"+(Integer.toBinaryString(Instructions[x]))+"\tOpCode:\t:::"+opcode+"\tsrc1:\t"+srcReg1test);
}
return opcode;
}
*/
public void testrun()
{
for(int x=0;x<Instructions.length;x++)
{
address = startaddress+(4*x);
opcode = Instructions[x]>>>26;
destreg = (Instructions[x]&masksDst)>>>11;
srcReg1=(Instructions[x]&masks1)>>>21;
srcReg2 =(Instructions[x]&masks2dst)>>>16;
sdReg=(Instructions[x]&masks2dst)>>>16;
functcode=(Instructions[x]&maskFunc);
offset=(short) (Instructions[x]&maskoffset);
offaddress=startaddress+offset;
String functionL = null;
if(opcode==0)
{
{
if(Integer.toHexString(functcode)=="20"){
functionR = "add";
continue;
}
else if(Integer.toHexString(functcode)=="22")
{
functionR = "sub";
continue;
}
else if(Integer.toHexString(functcode)=="24")
{
functionR = "and";
continue;
}
else if(Integer.toHexString(functcode)=="25")
{
functionR = "or";
continue;
}
System.out.println(Integer.toHexString(address)+"\t"+functionR+"$"+destreg+", $"+srcReg1+", $"+srcReg2);
}
}
else
{
if(opcode == 35){
functionL = "lw";
System.out.println(Integer.toHexString(address)+"\t"+functionL+" $"+sdReg+", "+offset+", "+"("+srcReg1+")");
continue;
}
else if(opcode == 4){
functionL = "beq";
System.out.println(Integer.toHexString(address)+"\t"+functionL+" $"+sdReg+", $"+srcReg1+", address "+Integer.toHexString(offaddress));
continue;
}
else if (opcode == 43){
functionL = "sw";
System.out.println(Integer.toHexString(address)+"\t"+functionL+" $"+sdReg+", "+offset+", "+"("+srcReg1+")");
continue;
}
else if (opcode == 5){
functionL = "bne";
System.out.println(Integer.toHexString(address)+"\t"+functionL+" $"+sdReg+", $"+srcReg1+", address "+Integer.toHexString(offaddress));
continue;}
}
}
}
public static void main(String[] args) {
// TODO Auto-generated method stub
Decoder Assemble = new Decoder();
System.out.println(Decoder.test);
System.out.println();
System.out.println(Integer.toHexString(functcode0));
System.out.println();
System.out.println(Integer.toHexString(functcode3));
System.out.println();
System.out.println(Integer.toHexString(functcode5));
System.out.println();
System.out.println(Integer.toHexString(functcode7));
System.out.println();
System.out.println(Integer.toHexString(functcode8));
System.out.println();
Assemble.testrun();
}
}
Actual output:
22
20
24
20
25
7a060 null$21, $17, $13
7a064 lw $19, 24, (23)
7a068 beq $7, $21, address 7a064
7a06c null$19, $19, $8
7a070 sw $19, 24, (12)
7a074 null$15, $19, $9
7a078 sw $15, -12, (12)
7a07c null$12, $12, $12
7a080 null$21, $21, $4
7a084 bne $15, $12, address 7a056
7a088 lw $25, -16, (18)
intended:
22
20
24
20
25
7a060 sub$21, $17, $13
7a064 lw $19, 24, (23)
7a068 beq $7, $21, address 7a064
7a06c add$19, $19, $8
7a070 sw $19, 24, (12)
7a074 and$15, $19, $9
7a078 sw $15, -12, (12)
7a07c add$12, $12, $12
7a080 null$21, $21, $4
7a084 or $15, $12, address 7a056
7a088 lw $25, -16, (18)
Thanks in advance.
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