Fix reset() issue with dynarec flushing

On a reset bios_swi_entrypoint can end up pointing to code over the
watermark, due to block_lookup_address_arm looking up the function
instead of translating it.
Fix it by making flush and init different functions (albeit similar).

Tested by running and resetting games automatically, causing ~10% of
games to crash.

cheats.c

@@ -60,7 +60,7 @@ static void update_hook_codebreaker(cheat_type *cheat)
         u32 pcaddr = 0x08000000 | (address & 0x1ffffff);
         #ifdef HAVE_DYNAREC
         if (cheat_master_hook != pcaddr)
-           init_caches();   /* Flush caches to install hook */
+           flush_dynarec_caches();   /* Flush caches to install hook */
         #endif
         cheat_master_hook = pcaddr;
         return;   /* Only support for one hook */

cpu.h

@@ -164,7 +164,8 @@ extern u32 rom_branch_hash[ROM_BRANCH_HASH_SIZE];
 void flush_translation_cache_rom(void);
 void flush_translation_cache_ram(void);
 void dump_translation_cache(void);
-void init_caches(void);
+void init_dynarec_caches(void);
+void flush_dynarec_caches(void);
 void init_emitter(bool);
 void init_bios_hooks(void);
 

cpu_threaded.c

@@ -3343,6 +3343,7 @@ void init_bios_hooks(void)
 
 void flush_translation_cache_ram(void)
 {
+  /* Flushes RAM caches avoiding doing too much work (ie. wiping unused memory) */
   flush_ram_count++;
   /*printf("ram flush %d (pc %x), %x to %x, %x to %x\n",
    flush_ram_count, reg[REG_PC], iwram_code_min, iwram_code_max,
@@ -3380,15 +3381,32 @@ void flush_translation_cache_ram(void)
 
 void flush_translation_cache_rom(void)
 {
+  /* We flush the generated code except for everything below the watermark. */
   last_rom_translation_ptr = &rom_translation_cache[rom_cache_watermark];
   rom_translation_ptr      = &rom_translation_cache[rom_cache_watermark];
 
   memset(rom_branch_hash, 0, sizeof(rom_branch_hash));
 }
 
-void init_caches(void)
+void init_dynarec_caches(void)
 {
-  /* Ensure we wipe everything including the SMC mirrors */
+  /* Initialize caches so that we can start initalizing the emitter. */
+  rom_translation_ptr = last_rom_translation_ptr = &rom_translation_cache[0];
+  memset(rom_branch_hash, 0, sizeof(rom_branch_hash));
+
+  ram_translation_ptr = last_ram_translation_ptr = &ram_translation_cache[0];
+  memset(iwram, 0, 0x8000);
+  memset(&ewram[0x40000], 0, 0x40000);
+
+  ewram_code_min = 0;
+  ewram_code_max = 0x40000;
+  iwram_code_min = 0;
+  iwram_code_max = 0x8000;
+}
+
+void flush_dynarec_caches(void)
+{
+  /* Flush ROM and RAM caches. */
   flush_translation_cache_rom();
   ewram_code_min = 0;
   ewram_code_max = 0x40000;

libretro/libretro.c

@@ -803,8 +803,9 @@ static void check_variables(int started_from_load)
       else if (strcmp(var.value, "enabled") == 0)
          dynarec_enable = 1;
 
+      /* Flush dynarec cache to ensure we do not execute old code */
       if (dynarec_enable != prevvalue)
-         init_caches();
+         flush_dynarec_caches();
    }
    else
       dynarec_enable = 1;

main.c

@@ -100,8 +100,8 @@ void init_main(void)
   video_count = 960;
 
 #ifdef HAVE_DYNAREC
+  init_dynarec_caches();
   init_emitter(gamepak_must_swap());
-  init_caches();
 #endif
 }
 

savestate.c

@@ -103,7 +103,7 @@ bool gba_load_state(const void* src)
   // Reset most of the frame state and dynarec state
 #ifdef HAVE_DYNAREC
   if (dynarec_enable)
-    init_caches();
+    flush_dynarec_caches();
 #endif
 
   instruction_count = 0;