Address Copilot review: OOB dummy ROM, CI test path, document RAM map

Made-with: Cursor

Author: JoeMatt

.github/workflows/c-cpp.yml

@@ -199,8 +199,8 @@ jobs:
         else
           LDFLAGS=""
         fi
-        $CC -O2 -Wall -o test_memory_map test/tools/test_memory_map.c $LDFLAGS
-        ./test_memory_map ./${{ matrix.config.artifact }}
+        $CC -O2 -Wall -o test/tools/test_memory_map test/tools/test_memory_map.c $LDFLAGS
+        ./test/tools/test_memory_map ./${{ matrix.config.artifact }}
 
     - name: RetroAchievements rc_libretro E2E test
       if: ${{ !matrix.config.emscripten && !matrix.config.android && !matrix.config.cross && runner.os != 'Windows' }}

.gitignore

@@ -1,6 +1,9 @@
 # Local E2E test build (downloads rcheevos tarball)
 /build/
 
+# Legacy local path (older CI recipe); keep ignored if present
+/test_memory_map
+
 # Build artifacts
 *.o
 *.so

libretro.c

@@ -998,7 +998,13 @@ bool retro_load_game(const struct retro_game_info *info)
    JaguarReset();
 
    /* Advertise the Jaguar memory map so frontends (RetroArch, etc.) can
-    * resolve emulated addresses to host buffers. Required for rcheevos. */
+    * resolve emulated addresses to host buffers. Required for rcheevos.
+    *
+    * rcheevos defines one logical system-RAM region for RC_CONSOLE_ATARI_JAGUAR:
+    * $000000-$1FFFFF (see rcheevos consoleinfo). RetroAchievements addresses for
+    * Jaguar are authored in that space. GPU-style paths mirror 2 MiB within
+    * $000000-$7FFFFF in JaguarReadByte, but M68K direct access in this core is
+    * only linear $000000-$1FFFFF without those mirrors (m68k_read_memory_*). */
    {
       static struct retro_memory_descriptor descs[1];
       static struct retro_memory_map memmap;

test/tools/test_memory_map.c

@@ -107,7 +107,8 @@ static void *load_sym(void *handle, const char *name)
  */
 static uint8_t *make_dummy_rom(size_t *size_out)
 {
-    size_t sz = 8192;
+    /* 0x2000 bytes is not enough: we patch instructions at file offset 0x2000 (8 KiB). */
+    size_t sz = 12288;
     uint8_t *rom = calloc(1, sz);
     if (!rom) { perror("calloc"); exit(1); }
 

test/tools/test_rcheevos_e2e.c

@@ -103,7 +103,7 @@ static void *load_sym(void *handle, const char *name)
 
 static uint8_t *make_dummy_rom(size_t *size_out)
 {
-    size_t sz = 8192;
+    size_t sz = 12288;
     uint8_t *rom = calloc(1, sz);
     if (!rom) { perror("calloc"); exit(1); }
     rom[0x404] = 0x00; rom[0x405] = 0x80;