static void swap() {
int left_var = variable(), right_var = variable();
int reg_one = next_register(), reg_two = next_register();
CodeGen(LOAD, reg_one, left_var, EMPTY_FIELD);
CodeGen(LOAD, reg_two, right_var, EMPTY_FIELD);
CodeGen(STORE, left_var, reg_two, EMPTY_FIELD);
CodeGen(STORE, right_var, reg_one, EMPTY_FIELD);
}
static int expr()
{
int reg, left_reg, right_reg;
switch (token) {
case '+':
next_token();
left_reg = expr();
right_reg = expr();
reg = next_register();
CodeGen(ADD, reg, left_reg, right_reg);
return reg;
case '*':
next_token();
left_reg = expr();
right_reg = expr();
reg = next_register();
CodeGen(MUL, reg, left_reg, right_reg);
return reg;
case '-':
next_token();
left_reg = expr();
right_reg = expr();
reg = next_register();
CodeGen(SUB, reg, left_reg, right_reg);
return reg;
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
return digit();
case 'a':
case 'b':
case 'c':
case 'd':
case 'e':
return variable();
default:
ERROR("Symbol %c unknown\n", token);
exit(EXIT_FAILURE);
}
}
int main(int argc, char *argv[])
{
const char *outfilename = "tinyL.out";
char *input;
FILE *infile;
printf("------------------------------------------------\n");
printf(" Compiler for tinyL\n Fall 2015\n");
printf("------------------------------------------------\n");
if (argc != 2) {
ERROR("Use of command:\n compile <tinyL file>\n");
exit(EXIT_FAILURE);
}
infile = fopen(argv[1], "r");
if (!infile) {
ERROR("Cannot open input file \"%s\"\n", argv[1]);
exit(EXIT_FAILURE);
}
outfile = fopen(outfilename, "w");
if (!outfile) {
ERROR("Cannot open output file \"%s\"\n", outfilename);
exit(EXIT_FAILURE);
}
input = read_input(infile);
buffer = input;
CodeGen(LOADI, 1024, 0, EMPTY_FIELD); /* set base register to 1024 */
program();
printf("\nCode written to file \"%s\".\n\n", outfilename);
free(input);
fclose(infile);
fclose(outfile);
return EXIT_SUCCESS;
}
static void read()
{
next_token();
if (!is_identifier(token)) {
ERROR("Expected identifier\n");
exit(EXIT_FAILURE);
}
CodeGen(READ, token, EMPTY_FIELD, EMPTY_FIELD);
next_token();
}
static void assign() {
int var = variable();
if (token == '=') {
next_token();
int reg = expr();
CodeGen(STORE, var, reg, EMPTY_FIELD);
} else {
ERROR("Syntax Error: In assignment, expected '='.\n");
}
}
static void print()
{
switch (token)
{
case '!':
next_token();
CodeGen(WRITE, token, EMPTY_FIELD, EMPTY_FIELD);
next_token();
return ;
}
}
static void assign()
{
char id;
int right_reg;
id = token;
next_token();
next_token();
right_reg = expr();
CodeGen(STORE, id, right_reg, EMPTY_FIELD);
return;
}
static void read()
{
switch (token)
{
case '?':
next_token();
CodeGen(READ, token, EMPTY_FIELD, EMPTY_FIELD);
next_token();
return;
}
}
static int variable() /* only called for R-values */
{
int reg;
if(!is_identifier(token)){
ERROR("Expected identifier\n");
exit(EXIT_FAILURE);
}
reg = next_register();
CodeGen(LOAD, reg, token, EMPTY_FIELD);
next_token();
return reg;
}
static int variable()
{
int reg;
if (!is_identifier(token)) {
ERROR("Expected identifier\n");
exit(EXIT_FAILURE);
}
reg = next_register();
CodeGen(LOADAI, 0, (token-'a')*4, reg); /* token - 'a' is offset of varible, *4 for byte address */
next_token();
return reg;
}
static int digit()
{
int reg;
if (!is_digit(token)) {
ERROR("Expected digit\n");
exit(EXIT_FAILURE);
}
reg = next_register();
CodeGen(LOADI, to_digit(token), reg, EMPTY_FIELD);
next_token();
return reg;
}
static void print()
{
next_token();
if(is_identifier(token)){
char variable = token;
CodeGen(OUTPUTAI, variable,EMPTY_FIELD,EMPTY_FIELD);
next_token();
}else {
ERROR("Expected a variable");
exit(EXIT_FAILURE);
}
/* YOUR CODE GOES HERE */
}
static void print() /* variables are handled explicitly without recursive call */
{
if (token != '!') {
ERROR("Expected print statement\n");
exit(EXIT_FAILURE);
}
next_token();
if (!is_identifier(token)) {
ERROR("Expected identifier\n");
exit(EXIT_FAILURE);
}
CodeGen(WRITE, token, EMPTY_FIELD, EMPTY_FIELD);
next_token();
}
static void print()
{
if(token != '!'){
ERROR("Expected '!', got %c\n", token);
exit(EXIT_FAILURE);
}
next_token();
if(!is_identifier(token)){
ERROR("Expected identifier, got %c\n", token);
exit(EXIT_FAILURE);
}
int offset = (token-'a')*4;
next_token();
CodeGen(OUTPUTAI, 0, offset, EMPTY_FIELD);
}
static void assign()
{
int reg;
if(!is_identifier(token)){
ERROR("Identifier expected, got %c\n", token);
exit(EXIT_FAILURE);
}
int offset = (token-'a')*4;
next_token();
if(token != '='){
ERROR("Expected '=', got %c\n", token);
exit(EXIT_FAILURE);
}
next_token();
reg = expr();
CodeGen(STOREAI, reg, 0, offset);
}
static void assign()
{
char ident;
int reg;
if (!is_identifier(token)) {
ERROR("Expected identifier\n");
exit(EXIT_FAILURE);
}
ident = token;
next_token();
if (token != '=') {
ERROR("Expected equal sign for assignment statement\n");
exit(EXIT_FAILURE);
};
next_token();
reg = expr();
CodeGen(STORE, ident, reg, EMPTY_FIELD);
}
static void assign()
{
char variable = token;
next_token();
if(token == '=') {
next_token();
int x = expr();
CodeGen(STOREAI, variable, x, EMPTY_FIELD);
next_token();
}else{
ERROR("Expected '=' ");
exit(EXIT_FAILURE);
}
/* YOUR CODE GOES HERE */
}
int CodeGen(NODPTR ptr)
{
int t1, t2, t;
switch(ptr->NodeType)
{
case CONST:
t = getFreeReg();
fprintf(fp, "MOV R%d %d\n", t, ptr->value);
return t;
break;
case VARIABLE:
t = getFreeReg();
fprintf(fp, "MOV R%d [%d]\n", t, ptr->stptr->binding);
return t;
break;
case RD:
t = getFreeReg();
fprintf(fp,"IN R%d\n", t);
fprintf(fp, "MOV [%d] R%d\n", ptr->Lptr->stptr->binding, t);
reg[t] = 0;
return 0;
break;
//Recursive cases.
case WE:
t2 = CodeGen(ptr->Lptr);
t1 = getFreeReg();
fprintf(fp, "MOV R%d R%d \n", t1, t2);
fprintf(fp,"OUT R%d\n", t1);
reg[t1] = 0;
reg[t2] = 0;
return 0;
break;
case PLUS:
t1 = CodeGen(ptr->Rptr);
t2 = CodeGen(ptr->Lptr);
fprintf(fp, "ADD R%d R%d\n", t2, t1);
reg[t1] = 0;
return t2;
break;
case MINUS:
t1 = CodeGen(ptr->Rptr);
t2 = CodeGen(ptr->Lptr);
fprintf(fp, "SUB R%d R%d\n", t2, t1);
reg[t1] = 0;
return t2;
break;
case MUL:
t1 = CodeGen(ptr->Rptr);
t2 = CodeGen(ptr->Lptr);
fprintf(fp, "MUL R%d R%d\n", t2, t1);
reg[t1] = 0;
return t2;
break;
case DIV:
t1 = CodeGen(ptr->Rptr);
t2 = CodeGen(ptr->Lptr);
fprintf(fp, "DIV R%d R%d\n", t2, t1);
reg[t1] = 0;
return t2;
break;
case SEQ:
CodeGen(ptr->Lptr);
if(ptr->Rptr)
CodeGen(ptr->Rptr);
return 0;
break;
case EQUAL:
t1 = CodeGen(ptr->Rptr);
fprintf(fp, "MOV [%d] R%d\n", ptr->Lptr->stptr->binding, t1);
return 0;
break;
}
}
int CodeGen(tnode* t)
{
int r,r1,r2;
int value;
int loc,l1,l2;
//r is the root of AST
//returntype of CodeGen is int that is it returns the register Number
switch(t->NODETYPE)
{
case NUM:
value=t->val;
r=getReg();
fprintf(fp,"MOV R%d, %d\n",r,value);
return r;
break;
case ID:
loc=t->var-'a';
r=getReg();
fprintf(fp, "MOV R%d, [%d]\n",r,loc);
return r;
break;
case PLUS:
r1=CodeGen(t->left);
r2=CodeGen(t->right);
fprintf(fp, "ADD R%d, R%d\n",r1,r2);
freeReg();
return r1;
break;
case MINUS:
r1=CodeGen(t->left);
r2=CodeGen(t->right);
fprintf(fp, "SUB R%d, R%d\n",r1,r2);
freeReg();
return r1;
break;
case MUL:
r1=CodeGen(t->left);
r2=CodeGen(t->right);
fprintf(fp, "MUL R%d, R%d\n",r1,r2);
freeReg();
return r1;
break;
case DIV:
r1=CodeGen(t->left);
r2=CodeGen(t->right);
fprintf(fp, "DIV R%d, R%d\n",r1,r2);
freeReg();
return r1;
break;
case MOD:
r1=CodeGen(t->left);
r2=CodeGen(t->right);
fprintf(fp, "MOD R%d, R%d\n",r1,r2);
freeReg();
return r1;
break;
case LT:
r1=CodeGen(t->left);
r2=CodeGen(t->right);
fprintf(fp, "LT R%d, R%d\n",r1,r2);
freeReg();
return r1;
break;
case GT:
r1=CodeGen(t->left);
r2=CodeGen(t->right);
fprintf(fp, "GT R%d, R%d\n",r1,r2);
freeReg();
return r1;
break;
case EQ:
r1=CodeGen(t->left);
r2=CodeGen(t->right);
fprintf(fp, "EQ R%d, R%d\n",r1,r2);
freeReg();
return r1;
break;
case EQUALS:
r1=getBinding(t->left);
r2=CodeGen(t->right);
fprintf(fp, "MOV [R%d], R%d\n",r1,r2);
freeReg();
freeReg();
return 0;
break;
case READ:
r=getBinding(t->left);
r1=getReg();
fprintf(fp, "IN R%d\n",r1);
fprintf(fp, "MOV [R%d], R%d\n",r,r1);
freeReg();
freeReg();
return 0;
break;
case WRITE:
r=CodeGen(t->left);
fprintf(fp, "OUT R%d\n",r);
freeReg();
return 0;
break;
case IF:
l1=getLabel();
r=CodeGen(t->left);
r1=getReg();
fprintf(fp, "MOV R%d, 0\n",r1);
fprintf(fp, "NE R%d, R%d\n",r,r1);
fprintf(fp, "JZ R%d, L%d\n",r,l1);
freeReg();
freeReg();
CodeGen(t->right);
fprintf(fp, "L%d:\n",l1);
return 0;
break;
case WHILE:
{
l1=getLabel();
l2=getLabel();
fprintf(fp, "L%d:\n",l1);
r=CodeGen(t->left);
r1=getReg();
fprintf(fp, "MOV R%d, 0\n",r1);
fprintf(fp, "NE R%d, R%d\n",r,r1);
fprintf(fp, "JZ R%d, L%d\n",r,l2);
freeReg();
freeReg();
CodeGen(t->right);
fprintf(fp, "JMP L%d\n",l1);
fprintf(fp, "L%d:\n",l2);
return 0;
}
break;
case CONNECT:
CodeGen(t->left);
CodeGen(t->right);
return 0;
break;
}
}
int CodeGen(NODPTR ptr)
{
int t1, t2, t, b;
switch(ptr->NodeType)
{
case CONST:
t = regcount++;
fprintf(Fp, "MOV R%d %d\t//\tMoving constant to a register.\n",
t, ptr->value);
return t;
break;
case TRUE:
t = regcount++;
fprintf(Fp, "MOV R%d %d\t//\tMoving true(1) to a register.\n",
t, ptr->value);
return t;
break;
case FALSE:
t = regcount++;
fprintf(Fp, "MOV R%d %d\t//\tMoving false(0) to a register.\n",
t, ptr->value);
return t;
break;
case VARIABLE:
t1 = regcount++;
if(ptr->Lstptr)
{
b = ptr->Lstptr->binding;
t2 = regcount++; // Need another register for storing base pointer.
fprintf(Fp, "MOV R%d BP\t//\tMoving base pointer to a register.\n", t2);
fprintf(Fp, "MOV R%d %d\t//\tStoring the relative address of the variable.\n",
t1, b);
fprintf(Fp, "ADD R%d R%d\t//\tAdding it with base pointer for absol. address\n",
t1, t2);
fprintf(Fp, "MOV R%d [R%d]\t//\tMoving variable contents to register.\n",
t1, t1);
regcount--;
}
else
{
b = ptr->Gstptr->binding;
fprintf(Fp, "MOV R%d %d\t//\tThe variable is global,so absolute address is used",
t1, b);
fprintf(Fp, "MOV R%d [R%d]\t//\tMoving variable contents to register.\n",
t1, t1);
}
return t1;
break;
//Recursive cases.
case ARRAY:
t1 = CodeGen(ptr->Rptr);
t = regcount++;
b = ptr->Lptr->Gstptr->binding;
fprintf(Fp, "MOV R%d %d\t//\tMoving binding field.\n", t, b);
fprintf(Fp, "ADD R%d R%d\t//\tAdding binding with the offset.\n", t1, t);
if(ArrFlag == 1)
fprintf(Fp, "MOV R%d [R%d]\t//\t...and loading it onto a register.\n",
t1,t1);
regcount--;
/*If ArrayFlag == 1
t1 will contain the value
otherwise
t1 will contain the absolute address */
return t1;
break;
case RD:
t = regcount++;
fprintf(Fp,"IN R%d\t\t//\tReading from input.\n", t);
if(ptr->Lptr->Lstptr)
b = ptr->Lptr->Lstptr->binding;
else
b = ptr->Lptr->Gstptr->binding;
if(ptr->Lptr->NodeType == VARIABLE)
fprintf(Fp, "MOV [%d] R%d\t//\tMoving the read content to variable.\n",
b, t);
else
{
// Done inorder to generate code to obtain array binding field.
ArrFlag = 0;
t1 = CodeGen(ptr->Lptr);
ArrFlag = 1;
fprintf(Fp, "MOV [R%d] R%d\t//\tMoving the read content to an array.\n",
t1, t);
regcount--;
}
regcount--;
break;
case WE:
t = CodeGen(ptr->Lptr);
fprintf(Fp,"OUT R%d\t\t//\tOutput the register content\n", t);
regcount--;
return 0;
break;
case PLUS:
t1 = CodeGen(ptr->Lptr);
t2 = CodeGen(ptr->Rptr);
fprintf(Fp, "ADD R%d R%d\t//\tPLUS\n", t1, t2);
regcount--;
return t1;
break;
case MINUS:
t1 = CodeGen(ptr->Lptr);
t2 = CodeGen(ptr->Rptr);
fprintf(Fp, "SUB R%d R%d\t//\tMINUS\n", t1, t2);
regcount--;
return t1;
break;
case MUL:
t1 = CodeGen(ptr->Lptr);
t2 = CodeGen(ptr->Rptr);
fprintf(Fp, "MUL R%d R%d\t//\tMUL\n", t1, t2);
regcount--;
return t1;
break;
case DIV:
t1 = CodeGen(ptr->Lptr);
t2 = CodeGen(ptr->Rptr);
fprintf(Fp, "DIV R%d R%d\t//\tDIV\n", t1, t2);
regcount--;
return t1;
break;
case SEQ:
CodeGen(ptr->Lptr);
if(ptr->Rptr)
CodeGen(ptr->Rptr);
return 0;
break;
case FUNC:
fprintf(Fp, "PUSH R0\n"); // 1. Push dummy value for storing return value.
for(t = 0; t < 8; t++)
fprintf(Fp, "PUSH R%d\n", t); // 2.Pushing machine status.
fprintf(Fp, "PUSH BP\n"); // 3. Storing caller's BP
NODPTR tmp = ptr->list;
while(tmp)
{
t = CodeGen(tmp); // 4.Pushing the parameters.
fprintf(Fp, "PUSH R%d\n", t);
tmp = tmp->next;
}
fprintf("CALL F%d\n", ptr->Lptr->Gstptr->binding); // 5.Calling the function.
// After function call.
tmp = ptr->list;
while(tmp) // 1. poping parameters
{
fprintf(Fp, "POP R0\n");
tmp = tmp->next;
}
fprintf(Fp, "POP BP\n"); //2 .Restoring BP
for(t = 7; t >= 0; t--)
fprintf(Fp, "POP R%d\n", t); // 2.Restoring machine status.
t1 = regcount++;
fprintf("MOV R%d [SP]\n", t1);//3. Copying back the return value.
return t1;
break;
case EQUAL:
t1 = CodeGen(ptr->Rptr);
if(ptr->Lptr->Lstptr)
b = ptr->Lptr->Lstptr->binding;
else
b = ptr->Lptr->Gstptr->binding;
if(ptr->Lptr->NodeType == VARIABLE)
fprintf(Fp, "MOV [%d] R%d\t//\tAssigning register contents to variable\n",
b, t1);
else
{
// Done inorder to generate code to obtain array binding field.
ArrFlag = 0;
t2 = CodeGen(ptr->Lptr);
ArrFlag = 1;
fprintf(Fp, "MOV [R%d] R%d\t//\tAssigning register contents to array\n",
t2, t1);
regcount--;
}
regcount--;
return 0;
break;
case GT:
t1 = CodeGen(ptr->Lptr);
t2 = CodeGen(ptr->Rptr);
fprintf(Fp, "GT R%d R%d\t//\tGreater than.\n", t1, t2);
regcount--;
return t1;
break;
case LT:
t1 = CodeGen(ptr->Lptr);
t2 = CodeGen(ptr->Rptr);
fprintf(Fp, "LT R%d R%d\t//\tLesser than.\n", t1, t2);
regcount--;
return t1;
break;
case GTE:
t1 = CodeGen(ptr->Lptr);
t2 = CodeGen(ptr->Rptr);
fprintf(Fp, "GE R%d R%d\t//\tGreater than or equal.\n", t1, t2);
regcount--;
return t1;
break;
case LTE:
t1 = CodeGen(ptr->Lptr);
t2 = CodeGen(ptr->Rptr);
fprintf(Fp, "LE R%d R%d\t//\tLesser than or equal.\n", t1, t2);
regcount--;
return t1;
break;
case ISEQUAL:
t1 = CodeGen(ptr->Lptr);
t2 = CodeGen(ptr->Rptr);
fprintf(Fp, "EQ R%d R%d\t//\tIs equal.\n", t1, t2);
regcount--;
return t1;
break;
case NE:
t1 = CodeGen(ptr->Lptr);
t2 = CodeGen(ptr->Rptr);
fprintf(Fp, "NE R%d R%d\t//\tIs not equal.\n", t1, t2);
regcount--;
return t1;
break;
case AND:
t1 = CodeGen(ptr->Lptr);
t2 = CodeGen(ptr->Rptr);
fprintf(Fp, "MUL R%d R%d\t//\tAND operation.\n", t1, t2);
regcount--;
return t1;
break;
case OR:
t1 = CodeGen(ptr->Lptr);
t2 = CodeGen(ptr->Rptr);
fprintf(Fp, "ADD R%d R%d\t//\tOR operation.\n", t1, t2);
fprintf(Fp, "MOV R%d %d\t//\tOR operation.\n", t2, 0);
fprintf(Fp, "NE R%d R%d\t//\tOR operation.\n", t1, t2);
regcount--;
return t1;
break;
case NOT:
t = regcount++;
t1 = CodeGen(ptr->Lptr);
fprintf(Fp, "MOV R%d %d\t//\tNOT operation.\n", t, 1);
fprintf(Fp, "SUB R%d R%d\t//\tNOT operation.\n", t, t1);
regcount--;
return t;
break;
case IF_THEN:
t1 = Branching_Label++;
t = CodeGen(ptr->Lptr);
fprintf(Fp, "JZ R%d L%d\t// If then\n", t, t1);
regcount--; // Freeing the register.
CodeGen(ptr->Rptr);
fprintf(Fp, "L%d:\t\t// Endif\n",t1);
return 0;
break;
case IF_THEN_ELSE:
t = CodeGen(ptr->Lptr);
// Two labels are needed for if else
t1 = Branching_Label++;
t2 = Branching_Label++;
fprintf(Fp, "JZ R%d L%d\t// If then else\n", t, t1);
regcount--; // Freeing the register.
CodeGen(ptr->Mptr);
fprintf(Fp, "JMP L%d\n", t2);
fprintf(Fp, "L%d:\t\t// ...else\n", t1);
CodeGen(ptr->Rptr);
fprintf(Fp, "L%d:\t\t// End if else\n",t2);
return 0;
break;
case DO_WHILE:
// Two labels are needed for while do
t1 = Branching_Label++;
t2 = Branching_Label++;
fprintf(Fp, "L%d:\n",t1);
t = CodeGen(ptr->Lptr);
fprintf(Fp, "JZ R%d L%d\t// While do\n", t, t2);
regcount--; // Freeing the register.
CodeGen(ptr->Rptr);
fprintf(Fp, "JMP L%d\t\t// Endwhile\n", t1);
fprintf(Fp, "L%d:\n",t2);
return 0;
break;
}
}
static void print() {
int var = variable();
CodeGen(WRITE, var, EMPTY_FIELD, EMPTY_FIELD);
}
static void read() {
int var = variable();
CodeGen(READ, var, EMPTY_FIELD, EMPTY_FIELD);
}