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assem.cc
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assem.cc
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/*
PAUL LEIMER
2/8/2018
NEXT UP:
Now, compile to machine code (forget parser for now to verify syntax)
NEXT:
make immediate masks so that negative numbers do not overwrite instructions
also make assem.h instead of including everything in sim.h to help with late projects
*/
#include "assem.h"
#include "sim_pipe.h"
using namespace std;
const char * WHITE_SPACE = " \t"; //space and tab
class eofException: public exception{
virtual const char* what() const throw(){
return "End of file.";
}
} eofExc;
void assembler::assemble(string path, byte * inst_memory){
//compile to machine code - check type, line and column to decide what equivalent machine
//code and store into instruction memory
vector<token> currInst;
vector<token> labels;
lexer lex(path);
int instruction;
int inst_mem_ptr = 0;
while(true){ //build list of labels before compiling rest
try{
currInst = lex.get();
for (token tok: currInst){
if(tok.getType() == LABEL){
labels.push_back(tok);
break;
}
}
}
catch(eofException){break;}
}
lex.reset_file_pointer();
while(true){
try{
currInst = lex.get(); //one line of instructions
instruction = 0;
for (token tok: currInst){ //compile instruction
switch(tok.getType()){
case OPCODE:{
instruction = this->mapCode(tok);
instruction = instruction << (INST_SIZE - OP_SIZE);
break;
}
case REGISTER: {//registers
string reg = tok.getCargo();
//get register number
for(unsigned int i=1;i<reg.length();i++){
reg[i-1] = reg[i];
}
reg.pop_back();
unsigned int regNum = stoi(reg);
if(tok.getCol() == 1)
regNum = regNum << (INST_SIZE - OP_SIZE - REG_REF_SIZE); //rd
if(tok.getCol() == 2)
regNum = regNum << (INST_SIZE - OP_SIZE - REG_REF_SIZE*2); //rs
if(tok.getCol() == 3)
regNum = regNum << (INST_SIZE - OP_SIZE - REG_REF_SIZE*3); //rt
instruction = instruction | regNum;
break;
}
case DECNUM: {//immediate
if(tok.getCol() > 2){
string strNum = tok.getCargo();
int num = stoi(strNum);
num &= IMM_MASK;
instruction = instruction | num;
}
break;
}
case HEXNUM: {//immediate
if(tok.getCol() > 2){
string strNum = tok.getCargo();
strNum = strNum.substr(2,strNum.length());
int num = stoi(strNum,nullptr,16);
num &= IMM_MASK;
instruction = instruction | num;
}
break;
}
case BINUM: {//immediate
if(tok.getCol() > 2){
string strNum = tok.getCargo();
strNum = strNum.substr(2,strNum.length());
int num = stoi(strNum,nullptr,2);
num &= IMM_MASK;
instruction = instruction | num;
}
break;
}
case REGOFFSET:{
if(tok.getCol() > 1){
string cargo = tok.getCargo();
string regStr, numStr;
int num;
numStr = cargo.substr(0, cargo.find('('));
regStr = cargo.substr(cargo.find('(')+1, cargo.find(')')-2);
//determin register number
unsigned int regNum = stoi(regStr.substr(1));
regNum = regNum << (INST_SIZE - OP_SIZE - REG_REF_SIZE*2);
//immediate
num = stoi(numStr);
instruction = instruction | regNum | num;
}
break;
}
/*case LABEL: {
//this builds vector full of LABEL tokens that have all information for referencing later
labels.push_back(tok);
for(token t: labels){
cout << "Token: " << t.getCargo() << " Line: " << t.getLine() << endl;
}
break;
}*/
case REF_LABEL: {
//find token in tokens vector, get linenumber, calculate offset
string cargo = tok.getCargo();
cargo += ":"; //Label token cargo contains the colon
int offset=0;
unsigned int pos = 0;
for(token item: labels){
if(cargo.compare(item.getCargo()) == 0)
break;
pos++;
}
//calculate offset
cout << "Branch line is: " << tok.getLine() << endl;
cout << "The label line is: "<< labels[pos].getLine() << endl;
offset = -1*(tok.getLine() - labels[pos].getLine());
offset &= LABEL_MASK;
cout << "Offset is: " << hex << offset << endl;
instruction = instruction | offset;
break;
}
default:
break;
}
}
//store instruction into instruction memory
//in four iterations, shift instruction into four bytes
/*bitset<32> y(instruction);
cout << y << endl;*/
for (int i=3;i>=0;i--){ //four bytes in each instruction
//opcode in first byte (order), operands after
*(inst_memory + inst_mem_ptr) = instruction >> 8*i;
inst_mem_ptr++;
}
}
catch(eofException){break;}
}
}
byte assembler::mapCode(token tok){ //return binary opcode value from token string
string cargo = tok.getCargo();
if(cargo.compare("LW")==0)
return (byte)(LW);
if(cargo.compare("SW")==0)
return (byte)(SW);
if(cargo.compare("ADD")==0)
return (byte)(ADD);
if(cargo.compare("ADDI")==0)
return (byte)(ADDI);
if(cargo.compare("SUB")==0)
return (byte)(SUB);
if(cargo.compare("SUBI")==0)
return (byte)(SUBI);
if(cargo.compare("XOR")==0)
return (byte)(XOR);
if(cargo.compare("XORI")==0)
return (byte)(XORI);
if(cargo.compare("OR")==0)
return (byte)(OR);
if(cargo.compare("ORI")==0)
return (byte)(ORI);
if(cargo.compare("AND")==0)
return (byte)(AND);
if(cargo.compare("ANDI")==0)
return (byte)(ANDI);
if(cargo.compare("BLTZ")==0)
return (byte)(BLTZ);
if(cargo.compare("BEQZ")==0)
return (byte)(BEQZ);
if(cargo.compare("BNEZ")==0)
return (byte)(BNEZ);
if(cargo.compare("BLTZ")==0)
return (byte)(BLTZ);
if(cargo.compare("BGTZ")==0)
return (byte)(BGTZ);
if(cargo.compare("BLEZ")==0)
return (byte)(BLEZ);
if(cargo.compare("BGEZ")==0)
return (byte)(BGEZ);
if(cargo.compare("JUMP")==0)
return (byte)(JUMP);
if(cargo.compare("EOP")==0)
return (byte)(EOP);
return 0xFC; //bad value
}
lexer::lexer(string path){
lineIndex = 0;
istringstream iss (path);
string token;
while(getline(iss,token,'.'));
if (token.compare("asm") != 0) { //check if valid file
cout << "Invalid file. Exiting..." << endl;
return;
}
asmFile.open(path.c_str());
}
lexer::~lexer(){
}
void lexer::reset_file_pointer(){
lineIndex = 0;
asmFile.clear(); //return to beginning of file
asmFile.seekg(0, ios::beg);
}
vector<token> lexer::get(){
//get next line and divide into tokens, return vector of tokens
string line;
vector<token> tokens;
tokenType type;
unsigned int column = 0;
getline(asmFile, line);
if(!asmFile){
if(!asmFile.eof()) cout << "Error in file\n";
throw eofExc;
}
vector<string> token_strs; //this needs to be deleted before refilling
split(line, WHITE_SPACE, token_strs); //get token strings for one line
//create token for each entry in token_strs
for (string token_str : token_strs){
type = detType(token_str, column);
if (type == UNDEF){
cout << "There was an undefined type: " << token_str << endl;
}
else{
tokens.push_back(token(token_str, lineIndex, column, type));
if (type != LABEL){
++column;
}
}
}
++lineIndex;
return tokens;
}
tokenType lexer::detType(string token_str, unsigned int column){
//check all that must start with alphabetic letter
if (isalpha(token_str[0]) != 0){
if (column == 0 && token_str.back() == ':') //check for label (check column and end character)
return LABEL;
else { //check for register
if (token_str[0] == 'R'){
string regNum;
for(unsigned int i=1;i<token_str.length();i++){
regNum.push_back(token_str[i]);
}
int reg = stoi(regNum);
if ((0 <= reg) && (reg < NUM_GP_REGISTERS)) return REGISTER;
}
}
if (column > 1) return REF_LABEL;
//check for opcode type
if(token_str.back() != ':'){
return OPCODE;
}
}
else {
//check for DECNUM
bool isNum = true;
for (char c: token_str){
if(!isdigit(c)){
isNum = false;
}
}
if(isNum) return DECNUM;
//check for HEXNUM
if((token_str[0] == '0') && (toupper(token_str[1]) == 'X'))
return HEXNUM;
//check for REGOFFSET
if (token_str.find("(") != string::npos)
return REGOFFSET;
}
return UNDEF; //MUST BE CHANGED
}
void lexer::split(const string &s, const char* delim, vector<string> & v){
char * dup = strdup(s.c_str());
char * token = strtok(dup, delim);
while(token != NULL){
v.push_back(string(token));
token = strtok(NULL, delim);
}
free(dup);
}
token::token(string cargo, unsigned int lineIndex, unsigned int column, tokenType type){
//create token variables
/*
string cargo;
string sourceText;
unsigned int lineIndex;
unsigned int column;
string type;*/
this->cargo = cargo;
this->lineIndex = lineIndex;
this->column = column;
this->type = type;
}
tokenType token::getType(){
return this->type;
}
unsigned int token::getLine(){
return this->lineIndex;
}
unsigned int token::getCol(){
return this->column;
}
string token::getCargo(){
return this->cargo;
}
//token print statement
ostream& operator<< (ostream& stream, const token& tok){
//display function for each token
const char* s = 0;
#define PROCESS_VAL(p) case(p): s = #p; break;
switch(tok.type){
PROCESS_VAL(LABEL);
PROCESS_VAL(REF_LABEL);
PROCESS_VAL(OPCODE);
PROCESS_VAL(REGISTER);
PROCESS_VAL(DECNUM);
PROCESS_VAL(HEXNUM);
PROCESS_VAL(BINUM);
PROCESS_VAL(COMMENT);
PROCESS_VAL(REGOFFSET);
PROCESS_VAL(UNDEF);
}
#undef PROCESS_VAL
stream << tok.cargo << " " << s << " " << tok.lineIndex << " " << tok.column;
return stream;
}