Add HOST_PROMPT_SUPPORT (#13039)

Marlin/src/gcode/host/M115.cpp

@@ -132,13 +132,20 @@ void GcodeSuite::M115() {
       #endif
     );
 
-    // EMERGENCY_PARSER (M108, M112, M410)
+    // EMERGENCY_PARSER (M108, M112, M410, M876)
     cap_line(PSTR("EMERGENCY_PARSER")
       #if ENABLED(EMERGENCY_PARSER)
         , true
       #endif
     );
 
+    // PROMPT SUPPORT (M876)
+    cap_line(PSTR("PROMPT_SUPPORT")
+      #if ENABLED(HOST_PROMPT_SUPPORT)
+        , true
+      #endif
+    );
+
     // AUTOREPORT_SD_STATUS (M27 extension)
     cap_line(PSTR("AUTOREPORT_SD_STATUS")
       #if ENABLED(AUTO_REPORT_SD_STATUS)

Marlin/src/gcode/host/M876.cpp

@@ -0,0 +1,37 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (C) 2016 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (C) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+#include "../../inc/MarlinConfig.h"
+
+#if ENABLED(HOST_PROMPT_SUPPORT) && DISABLED(EMERGENCY_PARSER)
+
+#include "../../feature/host_actions.h"
+#include "../gcode.h"
+#include "../../Marlin.h"
+
+/**
+ * M876: Handle Prompt Response
+ */
+void GcodeSuite::M876() {
+  if (parser.seenval('S')) host_response_handler((uint8_t)parser.value_int());
+}
+
+#endif // HOST_PROMPT_SUPPORT && !EMERGENCY_PARSER