Merge pull request #46 from bdunahu/bdunahu

 Ensure all stages only do work if they are not 'OK' 

1 files changed, 25 insertions, 19 deletions

diff --git a/src/sim/mm.cc b/src/sim/mm.cc
index cd85056..07a362b 100644
--- a/src/sim/mm.cc
+++ b/src/sim/mm.cc
@@ -4,26 +4,32 @@
 #include "response.h"
 #include "stage.h"
 
-MM::MM(Stage *stage) : Stage(stage) { this->id = MEM; } 
+MM::MM(Stage *stage) : Stage(stage) { this->id = MEM; }
 
-void MM::advance_helper() {
-	Response r;
+void MM::advance_helper()
+{
 	signed int data;
-	if(this->curr_instr){
-		if (this->curr_instr->get_mnemonic() == LOAD) {
-			r = this->storage->read_word(this->id, this->curr_instr->get_s1(), data);
-			if(r == OK){
-				this->status = OK;
-				this->curr_instr->set_s2(data);
-			}
-		} else if (this->curr_instr->get_mnemonic() == STORE) {
-			r = this->storage->write_word(this->id, this->curr_instr->get_s2(), this->curr_instr->get_s1());
-			if(r == OK){
-				this->status = OK;
-			}
-		} else {
-			// Mem has no work so just forward the instruction to WB
-			this->status = OK;
+
+	switch (this->curr_instr->get_mnemonic()) {
+	case LOAD:
+		this->status = this->storage->read_word(
+			this->id, this->curr_instr->get_s1(), data);
+		if (this->status == OK) {
+			this->curr_instr->set_s1(data);
+		} else
+			this->status = STALLED;
+		break;
+
+	case STORE:
+		// TODO signed issues, we aren't wrapping addresses
+		this->status = this->storage->write_word(
+			this->id, this->curr_instr->get_s2(), this->curr_instr->get_s1());
+		if (this->status != OK) {
+			this->status = STALLED;
 		}
-	} 
+		break;
+
+	default:
+		this->status = OK;
+	}
 }