Sound fixed and complete. More OpCodes to implement

Core/Cpu/Z80.cs

@@ -2181,6 +2181,28 @@ namespace Core.Cpu
                     // 3. Read the byte from memory and drop it into the L register (Low byte of HL)
                     HL.Low = ReadMemory(address6E);
 
+                    return 19;
+                case 0x70: // LD (IX+d), B
+                           // 1. Fetch the displacement byte and cast it to a signed sbyte
+                    sbyte offset70 = (sbyte)FetchByte();
+
+                    // 2. Calculate the exact memory address (IX + offset)
+                    ushort address70 = (ushort)(IX.Word + offset70);
+
+                    // 3. Write the B register (High byte of BC) into memory
+                    WriteMemory(address70, BC.High);
+
+                    return 19;
+                case 0x71: // LD (IX+d), C
+                           // 1. Fetch the displacement byte and cast it to a signed sbyte
+                    sbyte offset71 = (sbyte)FetchByte();
+
+                    // 2. Calculate the exact memory address (IX + offset)
+                    ushort address71 = (ushort)(IX.Word + offset71);
+
+                    // 3. Write the C register (Low byte of BC) into memory
+                    WriteMemory(address71, BC.Low);
+
                     return 19;
                 case 0x72: // LD (IX+d), D
                            // 1. Fetch the displacement byte and cast to a signed sbyte
@@ -2508,7 +2530,17 @@ namespace Core.Cpu
                     // 3. Write the contents of the D register (High byte of DE) into memory
                     WriteMemory(address72, DE.High);
 
-                    return 19; // 19 T-States
+                    return 19;
+                case 0x73: // LD (IY+d), E
+                           // 1. Fetch the displacement byte and cast it to a signed sbyte
+                    sbyte offset73 = (sbyte)FetchByte();
+
+                    // 2. Calculate the exact memory address (IY + offset)
+                    ushort address73 = (ushort)(IY.Word + offset73);
+
+                    // 3. Write the contents of the E register (Low byte of DE) into memory
+                    WriteMemory(address73, DE.Low);
+                    return 19;
                 case 0x74: // LD (IY+d), H
                            // 1. Fetch the displacement byte and cast it to a signed sbyte
                     sbyte offset74 = (sbyte)FetchByte();

Desktop/BeeperDevice.cs

@@ -7,6 +7,8 @@ namespace Desktop
     {
         private WaveOutEvent _waveOut;
         private BufferedWaveProvider _buffer;
+        private float _lastSample = 0.0f;
+        private float _lastFiltered = 0.0f;
 
         public BeeperDevice()
         {
@@ -25,16 +27,19 @@ namespace Desktop
         public void AddSample(bool isHigh)
         {
             //Buffer overrun check and dump
-            if (_buffer.BufferedDuration.TotalMilliseconds > 100)
+            while (_buffer.BufferedDuration.TotalMilliseconds > 80)
             {
-                _buffer.ClearBuffer();
+                Thread.Sleep(1);
             }
 
             // Convert the boolean into a physical sound wave (-0.2 or +0.2)
-            float sampleValue = isHigh ? 0.2f : -0.2f;
+            float rawSample = isHigh ? 0.2f : -0.2f;
+            float filteredSample = rawSample - _lastSample + 0.995f * _lastFiltered;
+            _lastSample = rawSample;
+            _lastFiltered = filteredSample;
 
             // Convert the float to bytes and drop it in the pipe
-            byte[] bytes = BitConverter.GetBytes(sampleValue);
+            byte[] bytes = BitConverter.GetBytes(filteredSample);
             _buffer.AddSamples(bytes, 0, 4);
         }
     }

Desktop/DebuggerForm.cs

@@ -835,6 +835,20 @@ namespace Desktop
                                 mnemonic = $"LD L, (IX{sign}{d})";
                                 instructionLength = 3;
                             }
+                            else if (ddOpcode == 0x71) // LD (IX+d), B
+                            {
+                                sbyte offset = (sbyte)_memoryBus.Read((ushort)(currentPc + 2));
+                                string sign = offset >= 0 ? "+" : "";
+                                mnemonic = $"LD (IX{sign}{offset}), B";
+                                instructionLength = 3;
+                            }
+                            else if (ddOpcode == 0x71) // LD (IX+d), C
+                            {
+                                sbyte offset = (sbyte)_memoryBus.Read((ushort)(currentPc + 2));
+                                string sign = offset >= 0 ? "+" : "";
+                                mnemonic = $"LD (IX{sign}{offset}), C";
+                                instructionLength = 3;
+                            }
                             else if (ddOpcode == 0x72) // LD (IX+d), D
                             {
                                 sbyte offset = (sbyte)_memoryBus.Read((ushort)(currentPc + 2));
@@ -1154,6 +1168,13 @@ namespace Desktop
                                 mnemonic = $"LD (IY{sign}{d}), D";
                                 instructionLength = 3;
                             }
+                            else if (fdOpcode == 0x73) // LD (IY+d), E
+                            {
+                                sbyte d = (sbyte)_memoryBus.Read((ushort)(currentPc + 2));
+                                string sign = d >= 0 ? "+" : "";
+                                mnemonic = $"LD (IY{sign}{d}), E";
+                                instructionLength = 3;
+                            }
                             else if (fdOpcode == 0x74) // LD (IY+d), H
                             {
                                 sbyte d = (sbyte)_memoryBus.Read((ushort)(currentPc + 2));

Desktop/Form1.cs

@@ -79,6 +79,8 @@ namespace Desktop
 
                         if (_isPaused)
                         {
+                            stopwatch.Restart();
+                            scanlineCount = 0;
                             Thread.Sleep(10);
                             continue;
                         }
@@ -174,6 +176,7 @@ namespace Desktop
 
         private void loadTAPToolStripMenuItem_Click(object sender, EventArgs e)
         {
+            _isPaused = true;
             using (OpenFileDialog ofd = new OpenFileDialog())
             {
                 ofd.Filter = "Spectrum TAP Files|*.tap";
@@ -183,9 +186,11 @@ namespace Desktop
                     _cpu._tapManager.LoadTapData(tapBytes);
                 }
             }
+            _isPaused = false;
         }
         private void openSNAToolStripMenuItem_Click(object sender, EventArgs e)
         {
+            _isPaused = true;
             using (OpenFileDialog ofd = new OpenFileDialog())
             {
                 ofd.Filter = "Snapshot Files (sna,z80)|*.sna";
@@ -195,6 +200,7 @@ namespace Desktop
                     _cpu.LoadSNA(snaBytes);
                 }
             }
+            _isPaused = false;
         }
 
         private void btnRun_Click(object sender, EventArgs e) => _isPaused = false;