From 4958c3d9a0a02c9104db6b4d0c1d9598a683757c Mon Sep 17 00:00:00 2001
From: Kevin Ramharak <kevin.ramharak@infocaster.net>
Date: Sun, 20 Jan 2019 13:32:48 +0100
Subject: [PATCH] add implementation for instruction aliases

---
 .../assembly/DefaultInstructionSet.java       | 24 +++++++++++++++----
 1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/Server/src/main/java/net/simon987/server/assembly/DefaultInstructionSet.java b/Server/src/main/java/net/simon987/server/assembly/DefaultInstructionSet.java
index a87f8ee..1f4ce55 100755
--- a/Server/src/main/java/net/simon987/server/assembly/DefaultInstructionSet.java
+++ b/Server/src/main/java/net/simon987/server/assembly/DefaultInstructionSet.java
@@ -4,6 +4,7 @@ import net.simon987.server.assembly.instruction.*;
 import net.simon987.server.logging.LogManager;
 
 import java.util.HashMap;
+import java.util.Set;
 
 /**
  * Default instruction set for the CPU
@@ -15,6 +16,11 @@ public class DefaultInstructionSet implements InstructionSet {
      */
     private HashMap<Integer, Instruction> instructionMap = new HashMap<>(32);
 
+    /**
+     * Map of aliasses, stored in mnemonic : Instruction format
+     */
+    private HashMap<String, Instruction> aliasesMap = new HashMap<>(16);
+
     private Instruction defaultInstruction;
 
     /**
@@ -32,7 +38,6 @@ public class DefaultInstructionSet implements InstructionSet {
         add(new AndInstruction());
         add(new OrInstruction());
         add(new ShlInstruction());
-        add(new SalInstruction()); //Alias is added
         add(new ShrInstruction());
         add(new XorInstruction());
         add(new TestInstruction());
@@ -46,6 +51,9 @@ public class DefaultInstructionSet implements InstructionSet {
         add(new SarInstruction());
         add(new IncInstruction());
         add(new DecInstruction());
+
+        // aliases
+        add(new SalInstruction());
     }
 
     /**
@@ -86,16 +94,22 @@ public class DefaultInstructionSet implements InstructionSet {
             }
         }
 
+        Instruction aliasedInstruction = aliasesMap.get(mnemonic.toLowerCase());
+        if (aliasedInstruction != null) {
+            return aliasedInstruction;
+        }
+
         return null;
     }
 
 
     @Override
     public void add(Instruction instruction) {
-        if (instructionMap.containsKey(instruction.getOpCode())) {
-            LogManager.LOGGER.fine(instruction.getMnemonic() + " instruction is an alias for " +
-                    instructionMap.get(instruction.getOpCode()).getMnemonic());
+        Instruction aliasedInstruction = instructionMap.get(instruction.getOpCode());
+        if (aliasedInstruction != null) {
+            aliasesMap.put(instruction.getMnemonic(), aliasedInstruction);
+        } else {
+            instructionMap.put(instruction.getOpCode(), instruction);
         }
-        instructionMap.put(instruction.getOpCode(), instruction);
     }
 }