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();