Using unsigned short and reversing instruction bytes in the bitwise way

cunyterg · Nov 4, 2016 · ca81e52 · ca81e52
1 parent 8385099
commit ca81e52
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Showing 3 changed files with 13 additions and 8 deletions.
diff --git a/src/PICHexDisassembler/Hex32Record.cs b/src/PICHexDisassembler/Hex32Record.cs
@@ -5,7 +5,7 @@ namespace PICHexDisassembler
 {
     public class Hex32Record
     {
-        public Hex32Record(byte byteCount, int address, byte recordType, short[] dataBytes, byte checksum)
+        public Hex32Record(byte byteCount, ushort address, byte recordType, ushort[] dataBytes, byte checksum)
         {
             ByteCount = byteCount;
             Address = address;
@@ -24,7 +24,7 @@ public Hex32Record(byte byteCount, int address, byte recordType, short[] dataByt
         public byte ByteCount { get; }
         public int Address { get; }
         public byte RecordType { get; }
-        public short[] DataBytes { get; }
+        public ushort[] DataBytes { get; }
         public byte Checksum { get; }
 
         public Instruction[] Instructions { get; }

diff --git a/src/PICHexDisassembler/HexParser.cs b/src/PICHexDisassembler/HexParser.cs
@@ -10,12 +10,12 @@ public Hex32Record ParseLine(string line)
             }
 
             var byteCount = byte.Parse(line.Substring(0, 2), System.Globalization.NumberStyles.HexNumber);
-            var address = int.Parse(line.Substring(2, 4), System.Globalization.NumberStyles.HexNumber);
+            var address = ushort.Parse(line.Substring(2, 4), System.Globalization.NumberStyles.HexNumber);
             var recordType = byte.Parse(line.Substring(6, 2), System.Globalization.NumberStyles.HexNumber);
             var checksum = byte.Parse(line.Substring(line.Length - 2), System.Globalization.NumberStyles.HexNumber);
 
             var wordsCount = byteCount / 2;
-            var dataBytes = new short[wordsCount];
+            var dataBytes = new ushort[wordsCount];
 
             for (int i = 0; i < wordsCount; i++)
             {
@@ -27,10 +27,15 @@ public Hex32Record ParseLine(string line)
             return new Hex32Record(byteCount, address, recordType, dataBytes, checksum);
         }
 
-        private short GetNextTwoBytesReversed(string line, int startIndex)
+        private ushort GetNextTwoBytesReversed(string line, int startIndex)
         {
-            var data = line.Substring(startIndex + 2, 2) + line.Substring(startIndex, 2);
-            return short.Parse(data, System.Globalization.NumberStyles.HexNumber);
+            var value = ushort.Parse(line.Substring(startIndex, 4), System.Globalization.NumberStyles.HexNumber);
+            return ReverseBytes(value);
+        }
+
+        private static ushort ReverseBytes(ushort value)
+        {
+            return (ushort)((value & 0x00FF) << 8 | (value & 0xFF00) >> 8);
         }
     }
 }
diff --git a/src/PICHexDisassembler/Instruction.cs b/src/PICHexDisassembler/Instruction.cs
@@ -26,7 +26,7 @@ public override string ToString()
             { 0x1000, 0xFC00, typeof(Bcf) },    // mask: 0001000000000000 opcodeMask: 1111110000000000
         };
 
-        internal static Instruction Parse(short dataBytes)
+        internal static Instruction Parse(ushort dataBytes)
         {
             foreach (var item in instructionMapping)
             {