Update ISystemSettingsServer.cs

Implement `GetSettingsItemValue`.

Ryujinx.Core/OsHle/Services/Set/ISystemSettingsServer.cs

@@ -19,7 +19,8 @@ namespace Ryujinx.Core.OsHle.Services.Set
             {
                 { 4,  GetFirmwareVersion2  },
                 { 23, GetColorSetId        },
-                { 24, SetColorSetId       }
+                { 24, SetColorSetId        },
+                { 38, GetSettingsItemValue }
             };
         }
 
@@ -83,5 +84,55 @@ namespace Ryujinx.Core.OsHle.Services.Set
             Context.Ns.Settings.ThemeColor = (ColorSet)ColorSetId;
             return 0;
         }
+        
+        public static long GetSettingsItemValue(ServiceCtx Context)
+        {
+            long ClassPos  = Context.Request.PtrBuff[0].Position;
+            long ClassSize = Context.Request.PtrBuff[0].Size;
+
+            long NamePos  = Context.Request.PtrBuff[1].Position;
+            long NameSize = Context.Request.PtrBuff[1].Size;
+
+            long ReplyPos  = Context.Request.ReceiveBuff[0].Position;
+            long ReplySize = Context.Request.ReceiveBuff[0].Size;
+
+            byte[] Class = AMemoryHelper.ReadBytes(Context.Memory, ClassPos, ClassSize);
+            byte[] Name  = AMemoryHelper.ReadBytes(Context.Memory, NamePos, NameSize);
+
+            string AskedSetting = Encoding.ASCII.GetString(Class).Trim('\0') + "!" + Encoding.ASCII.GetString(Name).Trim('\0');
+
+            NxSettings.Settings.TryGetValue(AskedSetting, out object NxSetting);
+
+            if (NxSetting != null)
+            {
+                byte[] SettingBuffer = new byte[ReplySize];
+
+                if (NxSetting is string StringValue)
+                {
+                    //Ain't be able to test, so we need to know what the size of ReplySize is...
+                    //Array.Resize(ref SettingBuffer, StringValue.Length);
+                    SettingBuffer = Encoding.ASCII.GetBytes(StringValue);
+                }
+                if (NxSetting is int IntValue)
+                {
+                    SettingBuffer = BitConverter.GetBytes(IntValue);
+                }
+                else if (NxSetting is bool BoolValue)
+                {
+                    SettingBuffer[0] = BoolValue ? (byte)1 : (byte)0;
+                }
+                else
+                {
+                    throw new NotImplementedException(NxSetting.GetType().Name);
+                }
+
+                AMemoryHelper.WriteBytes(Context.Memory, ReplyPos, SettingBuffer);
+
+                Context.Ns.Log.PrintInfo(Logging.LogClass.ServiceSet, $"{AskedSetting} set value: {NxSetting} as {NxSetting.GetType()}");
+            }
+            else Context.Ns.Log.PrintError(Logging.LogClass.ServiceSet, $"{AskedSetting} not found!");
+
+            return 0;
+        }
     }
 }