From 6e3588f36aedb6912505a1782151d104f6585770 Mon Sep 17 00:00:00 2001
From: Rob Loach <robloach@gmail.com>
Date: Tue, 17 Sep 2024 15:01:08 -0400
Subject: [PATCH 1/3] libretro: Add RETRO_ENVIRONMENT_GET_CORE_DATA and
 RETRO_ENVIRONMENT_SET_CORE_DATA

---
 dynamic.h                          |  1 +
 libretro-common/include/libretro.h | 25 +++++++++++++++++++++++++
 runloop.c                          | 12 ++++++++++++
 3 files changed, 38 insertions(+)

diff --git a/dynamic.h b/dynamic.h
index 79ed70ab16df..084ccf67d3eb 100644
--- a/dynamic.h
+++ b/dynamic.h
@@ -68,6 +68,7 @@ struct retro_core_t
 
    unsigned poll_type;
    uint8_t flags;
+   void *core_data; /* Arbitrary core data. @see RETRO_ENVIRONMENT_GET_CORE_DATA */
 };
 
 
diff --git a/libretro-common/include/libretro.h b/libretro-common/include/libretro.h
index f1764ef42959..dea823bb3d7e 100644
--- a/libretro-common/include/libretro.h
+++ b/libretro-common/include/libretro.h
@@ -2569,6 +2569,31 @@ enum retro_mod
  */
 #define RETRO_ENVIRONMENT_GET_FILE_BROWSER_START_DIRECTORY 80
 
+/**
+ * Sets a pointer to arbitrary data for the actively running core.
+ *
+ * This is can be set in either \c retro_init() or \c retro_load_game().
+ *
+ * @param[in] data <tt>void *</tt>. Pointer to the data to set.
+ * @return \c true if the environment call is available.
+ *
+ * @see RETRO_ENVIRONMENT_GET_CORE_DATA
+ */
+#define RETRO_ENVIRONMENT_SET_CORE_DATA 81
+
+/**
+ * Gets a pointer to arbitrary data for the actively running core.
+ *
+ * This is persistent for the lifetime of the core until \c retro_deinit() is called.
+ *
+ * @param[out] data <tt>void **</tt>. Pointer to the data that was set.
+ * May be \c NULL if the data was not set yet.
+ * @return \c true if the environment call is available.
+ *
+ * @see RETRO_ENVIRONMENT_SET_CORE_DATA
+ */
+#define RETRO_ENVIRONMENT_GET_CORE_DATA 82
+
 /**@}*/
 
 /**
diff --git a/runloop.c b/runloop.c
index 11e4a32f920b..69ea7ea19250 100644
--- a/runloop.c
+++ b/runloop.c
@@ -3583,6 +3583,18 @@ bool runloop_environment_cb(unsigned cmd, void *data)
             }
          }
          break;
+
+      case RETRO_ENVIRONMENT_SET_CORE_DATA:
+         runloop_st->current_core.core_data = data;
+         break;
+
+      case RETRO_ENVIRONMENT_GET_CORE_DATA:
+         if (data != NULL) {
+            void **core_data = (void **)data;
+            *core_data = runloop_st->current_core.core_data;
+         }
+         break;
+
       default:
          RARCH_LOG("[Environ]: UNSUPPORTED (#%u).\n", cmd);
          return false;

From 1368eddee60b251c9197354c357076117dcf8354 Mon Sep 17 00:00:00 2001
From: Rob Loach <robloach@gmail.com>
Date: Tue, 17 Sep 2024 15:45:05 -0400
Subject: [PATCH 2/3] libretro: Add docs around SET_CORE_INFO

---
 libretro-common/include/libretro.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libretro-common/include/libretro.h b/libretro-common/include/libretro.h
index dea823bb3d7e..36b37fe13b1e 100644
--- a/libretro-common/include/libretro.h
+++ b/libretro-common/include/libretro.h
@@ -2572,7 +2572,8 @@ enum retro_mod
 /**
  * Sets a pointer to arbitrary data for the actively running core.
  *
- * This is can be set in either \c retro_init() or \c retro_load_game().
+ * Intended for use as a substitute for global state, which is a common
+ * source of bugs. Can be set in either \c retro_init() or \c retro_load_game().
  *
  * @param[in] data <tt>void *</tt>. Pointer to the data to set.
  * @return \c true if the environment call is available.

From 7201865c2f8814b1e03e82a08e797c8f7203fe42 Mon Sep 17 00:00:00 2001
From: Rob Loach <robloach@gmail.com>
Date: Thu, 2 Jan 2025 17:55:22 -0500
Subject: [PATCH 3/3] Set RETRO_ENVIRONMENT_GET_CORE_DATA and
 RETRO_ENVIRONMENT_SET_CORE_DATA as experimental

---
 dynamic.h                          | 8 +++++++-
 libretro-common/include/libretro.h | 4 ++--
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/dynamic.h b/dynamic.h
index 084ccf67d3eb..0f1d238ee759 100644
--- a/dynamic.h
+++ b/dynamic.h
@@ -68,7 +68,13 @@ struct retro_core_t
 
    unsigned poll_type;
    uint8_t flags;
-   void *core_data; /* Arbitrary core data. @see RETRO_ENVIRONMENT_GET_CORE_DATA */
+
+   /**
+    * Arbitrary core data.
+    *
+    * @see RETRO_ENVIRONMENT_GET_CORE_DATA
+    */
+   void *core_data;
 };
 
 
diff --git a/libretro-common/include/libretro.h b/libretro-common/include/libretro.h
index f5a96ea697f2..de3613bfeb22 100644
--- a/libretro-common/include/libretro.h
+++ b/libretro-common/include/libretro.h
@@ -2584,7 +2584,7 @@ enum retro_mod
  *
  * @see RETRO_ENVIRONMENT_GET_CORE_DATA
  */
-#define RETRO_ENVIRONMENT_SET_CORE_DATA 81
+#define RETRO_ENVIRONMENT_SET_CORE_DATA (81 | RETRO_ENVIRONMENT_EXPERIMENTAL)
 
 /**
  * Gets a pointer to arbitrary data for the actively running core.
@@ -2597,7 +2597,7 @@ enum retro_mod
  *
  * @see RETRO_ENVIRONMENT_SET_CORE_DATA
  */
-#define RETRO_ENVIRONMENT_GET_CORE_DATA 82
+#define RETRO_ENVIRONMENT_GET_CORE_DATA (82 | RETRO_ENVIRONMENT_EXPERIMENTAL)
 
 /**@}*/