-
Notifications
You must be signed in to change notification settings - Fork 0
/
Disassembler.java
174 lines (147 loc) · 5.18 KB
/
Disassembler.java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.nio.file.FileSystems;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.logging.Handler;
import java.util.logging.FileHandler;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.util.logging.SimpleFormatter;
class Disassembler {
private static final Logger logger = createLogger();
private static final Instruction[] INSTRUCTION_TABLE = getInstructions();
private byte[] data;
private int index;
private int end;
private int digits;
private static class Instruction {
public final String mnem;
public final int size;
public Instruction(String m, int s) {
mnem = m;
size = s;
}
}
private static Logger createLogger() {
Handler fh = null;
try {
fh = new FileHandler("logs/Disassembler.java.log");
} catch (IOException e) {
e.printStackTrace();
System.exit(0);
}
Logger logger = Logger.getLogger(Disassembler.class.getName());
logger.setUseParentHandlers(false);
SimpleFormatter formatter = new SimpleFormatter();
fh.setFormatter(formatter);
logger.addHandler(fh);
return logger;
}
/*
* JSON array of arrays from file.
* Each instruction is represented as an array, like:
* ["mvi c,", 2]
* where the first element is the mnemonic and the second is the size of
* the instruction in bytes.
*
* The array indices correspond to the opcodes of the Intel 8080 (i.e. 0x00
* through 0xff)
*/
private static Instruction[] getInstructions() {
BufferedReader br = null;
Instruction[] table = new Instruction[256];
int count = 0;
String line = null;
try {
br = new BufferedReader(new FileReader("instructions.json"));
while (null != (line = br.readLine())) {
// Not a good implementation, but doesn't require other
// dependencies
if (line.length() < 23) {
continue;
}
final int first = line.indexOf("\"") + 1;
final int last = line.indexOf("\",");
final String mnem = line.substring(first, last);
final int size = Character.getNumericValue(line.charAt(20));
final Instruction instr = new Instruction(mnem, size);
table[count] = instr;
count++;
}
} catch (IOException e) {
e.printStackTrace();
System.exit(0);
} finally {
try {
if (null != br) {
br.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
return table;
}
public Disassembler(String filename) {
Path p = FileSystems.getDefault().getPath("", filename);
try {
data = Files.readAllBytes(p);
} catch (IOException e) {
e.printStackTrace();
System.exit(0);
}
index = 0;
end = data.length;
digits = String.valueOf(end).length();
}
private String output1Byte(final Instruction instr) {
return String.format("%04x %s", index, instr.mnem);
}
private String output2Byte(final Instruction instr, final int operand) {
if (instr.mnem.contains("out") || instr.mnem.contains("in")) {
return String.format("%04x %s$%02x", index, instr.mnem, operand);
}
return String.format("%04x %s#%02x", index, instr.mnem, operand);
}
private String output3Byte(final Instruction instr, final int[] operand) {
if (instr.mnem.contains("lxi")) {
return String.format("%04x %s#%02x%02x", index, instr.mnem,
operand[0], operand[1]);
}
return String.format("%04x %s$%02x%02x", index, instr.mnem, operand[0],
operand[1]);
}
public void run() {
while (index < end) {
// Convert signed byte
final int b = data[index] & 0xff;
final Instruction instr = INSTRUCTION_TABLE[b];
String msg = null;
if (instr.size == 1) {
msg = output1Byte(instr);
} else if (instr.size == 2) {
int operand = data[index + 1] & 0xff;
msg = output2Byte(instr, operand);
} else if (instr.size == 3) {
int[] operand = new int[2];
operand[0] = data[index + 2] & 0xff;
operand[1] = data[index + 1] & 0xff;
msg = output3Byte(instr, operand);
}
index += instr.size;
System.out.println(msg);
logger.log(Level.FINE, msg);
}
}
public static void main(String[] args) {
if (args.length != 1) {
System.out.println("Usage: java Disassembler [filename]");
System.exit(0);
}
String filename = args[0];
Disassembler d = new Disassembler(filename);
d.run();
}
}