Hack-Assembler/SymbolTable.cpp at master · francoiswnel/Hack-Assembler · GitHub

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
/*
 * Created by Francois W. Nel on 27 Jun 2016.
 */

#include "SymbolTable.h"

using namespace std;

SymbolTable::SymbolTable() {
    // Populate the table with predefined symbols.
    symbolAddressTable["SP"] = 0;
    symbolAddressTable["LCL"] = 1;
    symbolAddressTable["ARG"] = 2;
    symbolAddressTable["THIS"] = 3;
    symbolAddressTable["THAT"] = 4;
    symbolAddressTable["R0"] = 0;
    symbolAddressTable["R1"] = 1;
    symbolAddressTable["R2"] = 2;
    symbolAddressTable["R3"] = 3;
    symbolAddressTable["R4"] = 4;
    symbolAddressTable["R5"] = 5;
    symbolAddressTable["R6"] = 6;
    symbolAddressTable["R7"] = 7;
    symbolAddressTable["R8"] = 8;
    symbolAddressTable["R9"] = 9;
    symbolAddressTable["R10"] = 10;
    symbolAddressTable["R11"] = 11;
    symbolAddressTable["R12"] = 12;
    symbolAddressTable["R13"] = 13;
    symbolAddressTable["R14"] = 14;
    symbolAddressTable["R15"] = 15;
    symbolAddressTable["SCREEN"] = 16384;
    symbolAddressTable["KBD"] = 24576;
}

void SymbolTable::addEntry(string symbol, int address) {
    if (symbolAddressTable.find(symbol) == symbolAddressTable.end()) {
        symbolAddressTable[symbol] = address;
    }
}

bool SymbolTable::contains(string symbol) {
    return (symbolAddressTable.find(symbol) != symbolAddressTable.end());
}

int SymbolTable::getAddress(string symbol) {
    if (symbolAddressTable.find(symbol) != symbolAddressTable.end()) {
        return symbolAddressTable[symbol];
    }

    // If the table does not contain the symbol.
    return 0;
}