fix disk_next, add option for disk_prev

command.c

@@ -209,6 +209,7 @@ static const struct cmd_map map[] = {
    { "OVERLAY_NEXT",           RARCH_OVERLAY_NEXT },
    { "DISK_EJECT_TOGGLE",      RARCH_DISK_EJECT_TOGGLE },
    { "DISK_NEXT",              RARCH_DISK_NEXT },
+   { "DISK_PREV",              RARCH_DISK_PREV },   
    { "GRAB_MOUSE_TOGGLE",      RARCH_GRAB_MOUSE_TOGGLE },
    { "MENU_TOGGLE",            RARCH_MENU_TOGGLE },
 };

config.def.h

@@ -687,6 +687,7 @@ static const struct retro_keybind retro_keybinds_1[] = {
    { true, RARCH_OVERLAY_NEXT,             RETRO_LBL_OVERLAY_NEXT,         RETROK_UNKNOWN, NO_BTN, 0, AXIS_NONE },
    { true, RARCH_DISK_EJECT_TOGGLE,        RETRO_LBL_DISK_EJECT_TOGGLE,    RETROK_UNKNOWN, NO_BTN, 0, AXIS_NONE },
    { true, RARCH_DISK_NEXT,                RETRO_LBL_DISK_NEXT,            RETROK_UNKNOWN, NO_BTN, 0, AXIS_NONE },
+   { true, RARCH_DISK_PREV,                RETRO_LBL_DISK_PREV,            RETROK_UNKNOWN, NO_BTN, 0, AXIS_NONE },
    { true, RARCH_GRAB_MOUSE_TOGGLE,        RETRO_LBL_GRAB_MOUSE_TOGGLE,    RETROK_F11,     NO_BTN, 0, AXIS_NONE },
    { true, RARCH_MENU_TOGGLE,              RETRO_LBL_MENU_TOGGLE,          RETROK_F1,      NO_BTN, 0, AXIS_NONE },
 };

driver.h

@@ -126,6 +126,7 @@ enum
    RARCH_OVERLAY_NEXT,
    RARCH_DISK_EJECT_TOGGLE,
    RARCH_DISK_NEXT,
+   RARCH_DISK_PREV,
    RARCH_GRAB_MOUSE_TOGGLE,
 
    RARCH_MENU_TOGGLE,

general.h

@@ -159,6 +159,7 @@ enum basic_event
    RARCH_CMD_LOG_FILE_DEINIT,
    RARCH_CMD_DISK_EJECT_TOGGLE,
    RARCH_CMD_DISK_NEXT,
+   RARCH_CMD_DISK_PREV,
    RARCH_CMD_RUMBLE_STOP,
 };
 

input/input_common.c

@@ -1259,6 +1259,7 @@ const struct input_bind_map input_config_bind_map[RARCH_BIND_LIST_END_NULL] = {
       DECLARE_META_BIND(2, overlay_next,          RARCH_OVERLAY_NEXT, "Overlay next"),
       DECLARE_META_BIND(2, disk_eject_toggle,     RARCH_DISK_EJECT_TOGGLE, "Disk eject toggle"),
       DECLARE_META_BIND(2, disk_next,             RARCH_DISK_NEXT, "Disk next"),
+	  DECLARE_META_BIND(2, disk_prev,             RARCH_DISK_NEXT, "Disk prev"),
       DECLARE_META_BIND(2, grab_mouse_toggle,     RARCH_GRAB_MOUSE_TOGGLE, "Grab mouse toggle"),
 #ifdef HAVE_MENU
       DECLARE_META_BIND(1, menu_toggle,           RARCH_MENU_TOGGLE, "Menu toggle"),

intl/english.h

@@ -72,6 +72,7 @@
 #define RETRO_LBL_OVERLAY_NEXT "Next Overlay"
 #define RETRO_LBL_DISK_EJECT_TOGGLE "Disk Eject Toggle"
 #define RETRO_LBL_DISK_NEXT "Disk Swap Next"
+#define RETRO_LBL_DISK_PREV "Disk Swap Previous"
 #define RETRO_LBL_GRAB_MOUSE_TOGGLE "Grab mouse toggle"
 #define RETRO_LBL_MENU_TOGGLE "Menu toggle"
 

retroarch.c

@@ -1719,10 +1719,24 @@ static void check_disk_next(
    unsigned current   = control->get_image_index();
    if (num_disks && num_disks != UINT_MAX)
    {
-      /* Use "no disk" state when index == num_disks. */
+      unsigned new_index = current;
-      unsigned next_index = current >= num_disks ?
+      current < num_disks - 1 ? new_index++ : new_index;
-         0 : ((current + 1) % (num_disks + 1));
+      rarch_disk_control_set_index(new_index);
-      rarch_disk_control_set_index(next_index);
+   }
+   else
+      RARCH_ERR("Got invalid disk index from libretro.\n");
+}
+
+static void check_disk_prev(
+      const struct retro_disk_control_callback *control)
+{
+   unsigned num_disks = control->get_num_images();
+   unsigned current   = control->get_image_index();
+   if (num_disks && num_disks != UINT_MAX)
+   {
+      unsigned new_index = current;
+      current > 0 ? new_index-- : new_index;
+      rarch_disk_control_set_index(new_index);
    }
    else
       RARCH_ERR("Got invalid disk index from libretro.\n");
@@ -2602,10 +2616,21 @@ bool rarch_main_command(unsigned cmd)
                (const struct retro_disk_control_callback*)
                &g_extern.system.disk_control;
 
-            if (!control)
+            if (control->get_eject_state())
                check_disk_next(control);
          }
          break;
+      case RARCH_CMD_DISK_PREV:
+         if (g_extern.system.disk_control.get_num_images)
+         {
+            const struct retro_disk_control_callback *control = 
+               (const struct retro_disk_control_callback*)
+               &g_extern.system.disk_control;
+
+            if (control->get_eject_state())
+               check_disk_prev(control);
+         }
+         break;
       case RARCH_CMD_RUMBLE_STOP:
          {
             int i;

runloop.c

@@ -489,6 +489,8 @@ static int do_state_checks(
       rarch_main_command(RARCH_CMD_DISK_EJECT_TOGGLE);
    else if (BIT64_GET(trigger_input, RARCH_DISK_NEXT))
       rarch_main_command(RARCH_CMD_DISK_NEXT);
+   else if (BIT64_GET(trigger_input, RARCH_DISK_PREV))
+      rarch_main_command(RARCH_CMD_DISK_PREV);	  
 
    if (BIT64_GET(trigger_input, RARCH_RESET))
       rarch_main_command(RARCH_CMD_RESET);