Use positive logic in the sentinel variable for MOVN/MOVZ

EduMIPS64 · May 1, 2016 · e49c8b8 · e49c8b8
1 parent 12d63c3
commit e49c8b8
Show file tree

Hide file tree

Showing 2 changed files with 12 additions and 14 deletions.
diff --git a/src/org/edumips64/core/is/MOVN.java b/src/org/edumips64/core/is/MOVN.java
@@ -44,8 +44,8 @@ class MOVN extends ALU_RType {
   final String OPCODE_VALUE = "001011";
   private static final Logger logger = Logger.getLogger(MOVN.class.getName());
 
-  // Skip the Write Back if the predicate (RT != 0) is false
-  private boolean skipWB = false;
+  // Set to true if the Write Back stage should write data.
+  private boolean should_write = false;
 
 
   public MOVN() {
@@ -56,8 +56,7 @@ public MOVN() {
   public void EX() throws IrregularStringOfBitsException, IntegerOverflowException, TwosComplementSumException {
     if (TR[RT_FIELD].getValue() != 0) {
       TR[RD_FIELD].setBits(TR[RS_FIELD].getBinString(), 0);
-    } else {
-      skipWB = true;
+      should_write = true;
     }
 
     if (enableForwarding) {
@@ -67,9 +66,9 @@ public void EX() throws IrregularStringOfBitsException, IntegerOverflowException
 
   public void doWB() throws IrregularStringOfBitsException {
     // The doWB() method is overridden because it must check if the write
-    // on the registers must be done, checking the skipWB variable.
-    if (!skipWB) {
-      logger.info("Skipping WB as the predicate is false");
+    // on the registers must be done, checking the should_write variable.
+    if (should_write) {
+      logger.info("Writing to the dest register, since the condition is true.");
       cpu.getRegister(params.get(RD_FIELD)).setBits(TR[RD_FIELD].getBinString(), 0);
     }
 

diff --git a/src/org/edumips64/core/is/MOVZ.java b/src/org/edumips64/core/is/MOVZ.java
@@ -41,8 +41,8 @@ class MOVZ extends ALU_RType {
   final String OPCODE_VALUE = "001010";
   private static final Logger logger = Logger.getLogger(MOVZ.class.getName());
 
-  // Skip the Write Back if the predicate (RT == 0) is false
-  private boolean skipWB = false;
+  // Set to true if the Write Back stage should write data.
+  private boolean should_write = false;
 
   public MOVZ() {
     super.OPCODE_VALUE = OPCODE_VALUE;
@@ -51,8 +51,7 @@ public MOVZ() {
   public void EX() throws IrregularStringOfBitsException, IntegerOverflowException, TwosComplementSumException {
     if (TR[RT_FIELD].getValue() == 0) {
       TR[RD_FIELD].setBits(TR[RS_FIELD].getBinString(), 0);
-    } else {
-      skipWB = true;
+      should_write = true;
     }
 
     if (enableForwarding) {
@@ -62,9 +61,9 @@ public void EX() throws IrregularStringOfBitsException, IntegerOverflowException
   }
   public void doWB() throws IrregularStringOfBitsException {
     // The doWB() method is overridden because it must check if the write
-    // on the registers must be done, checking the skipWB variable.
-    if (!skipWB) {
-      logger.info("Skipping WB as the predicate is false");
+    // on the registers must be done, checking the should_write variable.
+    if (should_write) {
+      logger.info("Writing to the dest register, since the condition is true.");
       cpu.getRegister(params.get(RD_FIELD)).setBits(TR[RD_FIELD].getBinString(), 0);
     }