/*
* Description:
* Calls fetch and dispatches an instruction at the same cycle (if possible)
* Inputs:
* trace: instruction trace with all the instructions executed
* current_cycle: the cycle we are at
* Returns:
* None
*/
void fetch_To_dispatch(instruction_trace_t* trace, int current_cycle) {
/* ECE552: YOUR CODE GOES HERE */
/* ECE552 Assignment 3 - BEGIN CODE */
if(instr_queue_size < INSTR_QUEUE_SIZE &&
fetch_index <= sim_num_insn){
instruction_t *currInstr = get_instr(trace, fetch_index);
while(currInstr && (IS_TRAP(currInstr->op))){
fetch_index++;
currInstr = get_instr(trace, fetch_index);
}
if(currInstr){
currInstr->tom_dispatch_cycle = current_cycle;
fetch(trace);
}
}
//Resolve target and source operand dependence
//Set map table of r_out to tag which reservation
//station will produce the result
if(instr_front() && USES_FP_FU(instr_front()->op)){
int i;
for(i = 0; i < RESERV_FP_SIZE; i++){
if(!reservFP[i]){
reservFP[i] = instr_front();
//Make sure we mark the existing raw dependences
//BEFORE updating the map table with my target regs
markRAWDependence(reservFP[i]);
updateMapTable(reservFP[i]);
instr_pop();
break;
}
}
}
else if(instr_front() && (USES_INT_FU(instr_front()->op) || instr_front()->op == 0)){
int i;
for(i = 0; i < RESERV_INT_SIZE; i++){
if(!reservINT[i]){
reservINT[i] = instr_front();
markRAWDependence(reservINT[i]);
updateMapTable(reservINT[i]);
instr_pop();
break;
}
}
}
else if(instr_front() &&
(IS_COND_CTRL(instr_front()->op) ||
IS_UNCOND_CTRL(instr_front()->op))) {
instr_pop();
}
return;
/* ECE552 Assignment 3 - END CODE */
}
/*
* Description:
* Moves instruction(s) from the dispatch stage to the issue stage
* Inputs:
* current_cycle: the cycle we are at
* Returns:
* None
*/
void dispatch_To_issue(int current_cycle) {
/* ECE552 Assignment 4 - BEGIN CODE */
instruction_t* head = instr_queue[0];
if (head != NULL && head->tom_dispatch_cycle < current_cycle && head->tom_issue_cycle == 0) {
if (IS_COND_CTRL(head->op) || IS_UNCOND_CTRL(head->op)) {
head = NULL;
remove_head();
/* decrement the instr_queue_size as first instruction is dispatched*/
instr_queue_size = instr_queue_size - 1;
} else if (USES_INT_FU(head->op) || USES_FP_FU(head->op)) {
/* check if there is a reservation station available */
if (!is_rs_available(head->op)) {
return;
}
insn_struct* temp = set_rs_available(head->op, head);
temp->insn->tom_issue_cycle = current_cycle;
set_dependent_insn(temp);
/* Set the r_out mapping in the maptable */
int i;
for (i =0; i < 2; i++) {
if (head->r_out[i] != DNA) {
map_table[head->r_out[i]] = head;
}
}
temp = NULL;
head = NULL;
remove_head();
instr_queue_size = instr_queue_size - 1;
}
}
/* ECE552 Assignment 4 - END CODE */
}
/*
* Description:
* Moves instruction(s) from the dispatch stage to the issue stage
* Inputs:
* current_cycle: the cycle we are at
* Returns:
* None
*/
void dispatch_To_issue(int current_cycle) {
/* ECE552: YOUR CODE GOES HERE */
if (instr_queue[0] == NULL) {
return;
}
instruction_t* insn = instr_queue[0];
if (IS_UNCOND_CTRL(insn->op) || IS_COND_CTRL(insn->op)) {
dequeue();
return;
}
instruction_t** rs;
int free_idx = -1;
int rs_size;
if (USES_INT_FU(insn->op)) {
rs = reservINT;
rs_size = RESERV_INT_SIZE;
} else if (USES_FP_FU(insn->op)) {
rs = reservFP;
rs_size = RESERV_FP_SIZE;
} else {
assert(false);
}
int i;
for (i = 0; i < rs_size; i++) {
if (rs[i] == NULL) {
free_idx = i;
}
}
if (free_idx == -1) {
return;
}
rs[free_idx] = insn;
insn->tom_issue_cycle = current_cycle;
dequeue();
// Check dependencies on the map table.
int rin;
for (i = 0; i < 3; i++) {
rin = insn->r_in[i];
if (rin < 0 || rin == DNA) {
continue;
}
assert(rin < MD_TOTAL_REGS);
if (map_table[rin] != NULL) {
insn->Q[i] = map_table[rin];
}
}
// Update the dependencies on the map table.
int rout;
for (i = 0; i < 2; i++) {
rout = insn->r_out[i];
if (rout < 0 || rout == DNA) {
continue;
}
assert(rout < MD_TOTAL_REGS);
map_table[rout] = insn;
}
assert(rs[free_idx] == insn);
}