diff --git a/Core/apu.c b/Core/apu.c
index b3a8e8e..5919427 100644
--- a/Core/apu.c
+++ b/Core/apu.c
@@ -40,6 +40,8 @@ bool GB_apu_is_DAC_enabled(GB_gameboy_t *gb, unsigned index)
 
         case GB_NOISE:
             return gb->io_registers[GB_IO_NR42] & 0xF8;
+            
+        nodefault;
     }
 
     return false;
@@ -58,6 +60,8 @@ static uint8_t agb_bias_for_channel(GB_gameboy_t *gb, unsigned index)
             return 0;
         case GB_NOISE:
             return gb->apu.noise_channel.current_volume;
+            
+        nodefault;
     }
     return 0;
 }
@@ -257,7 +261,8 @@ static void render(GB_gameboy_t *gb)
             {left_volume * (1 - gb->apu_output.highpass_rate) + gb->apu_output.highpass_diff.left * gb->apu_output.highpass_rate,
                 right_volume * (1 - gb->apu_output.highpass_rate) + gb->apu_output.highpass_diff.right * gb->apu_output.highpass_rate};
 
-        case GB_HIGHPASS_MAX:;
+        case GB_HIGHPASS_MAX:
+        nodefault;
         }
 
     }
diff --git a/Core/defs.h b/Core/defs.h
index 0517b22..b512986 100644
--- a/Core/defs.h
+++ b/Core/defs.h
@@ -17,6 +17,9 @@
 #define unrolled
 #endif
 
+#define unreachable() __builtin_unreachable();
+#define nodefault default: unreachable()
+
 #ifdef GB_BIG_ENDIAN
 #define LE16(x) __builtin_bswap16(x)
 #define LE32(x) __builtin_bswap32(x)
diff --git a/Core/display.c b/Core/display.c
index 2e03039..1a36916 100644
--- a/Core/display.c
+++ b/Core/display.c
@@ -834,6 +834,8 @@ static void advance_fetcher_state_machine(GB_gameboy_t *gb)
             gb->fetcher_state++;
         }
         break;
+        
+        nodefault;
     }
 }
 
diff --git a/Core/joypad.c b/Core/joypad.c
index 3527742..db50f66 100644
--- a/Core/joypad.c
+++ b/Core/joypad.c
@@ -53,9 +53,7 @@ void GB_update_joyp(GB_gameboy_t *gb)
             }
             break;
 
-        default:
-            __builtin_unreachable();
-            break;
+        nodefault;
     }
     
     /* Todo: This assumes the keys *always* bounce, which is incorrect when emulating an SGB */
diff --git a/Core/mbc.c b/Core/mbc.c
index 82771eb..5ade9aa 100644
--- a/Core/mbc.c
+++ b/Core/mbc.c
@@ -77,6 +77,7 @@ void GB_update_mbc_mappings(GB_gameboy_t *gb)
                         gb->mbc_rom_bank++;
                     }
                     break;
+                nodefault;
             }
             break;
         case GB_MBC2:
@@ -121,6 +122,7 @@ void GB_update_mbc_mappings(GB_gameboy_t *gb)
             gb->mbc_ram_bank = gb->tpp1.ram_bank;
             gb->mbc_ram_enable = (gb->tpp1.mode == 2) || (gb->tpp1.mode == 3);
             break;
+        nodefault;
     }
 }
 
diff --git a/Core/memory.c b/Core/memory.c
index dd24f84..29d8534 100644
--- a/Core/memory.c
+++ b/Core/memory.c
@@ -360,6 +360,7 @@ static uint8_t read_mbc_ram(GB_gameboy_t *gb, uint16_t addr)
                     case 1: return gb->tpp1.rom_bank >> 8;
                     case 2: return gb->tpp1.ram_bank;
                     case 3: return gb->rumble_strength | gb->tpp1_mr4;
+                    nodefault;
                 }
             case 2:
             case 3:
@@ -533,8 +534,7 @@ static uint8_t read_high_memory(GB_gameboy_t *gb, uint16_t addr)
                                 oam[target >> 1] = bitwise_glitch_read(a, b, c);
                                 break;
                                 
-                            default:
-                                __builtin_unreachable();
+                            nodefault;
                         }
                         
                         for (unsigned i = 0; i < 8; i++) {
@@ -706,7 +706,7 @@ static uint8_t read_high_memory(GB_gameboy_t *gb, uint16_t addr)
                 }
                 return 0xFF;
         }
-        __builtin_unreachable();
+        unreachable();
     }
 
     if (addr == 0xFFFF) {
@@ -899,6 +899,7 @@ static void write_mbc(GB_gameboy_t *gb, uint16_t addr, uint8_t value)
                     }
             }
             break;
+            nodefault;
     }
     GB_update_mbc_mappings(gb);
 }
@@ -1243,7 +1244,7 @@ static void write_high_memory(GB_gameboy_t *gb, uint16_t addr, uint8_t value)
                 case GB_MODEL_SGB_PAL_NO_SFC:
                 case GB_MODEL_SGB2:
                 case GB_MODEL_SGB2_NO_SFC:
-                    __builtin_unreachable();
+                    unreachable();
             }
             return;
         }
diff --git a/Core/sm83_cpu.c b/Core/sm83_cpu.c
index 130bfb3..fdaf85d 100644
--- a/Core/sm83_cpu.c
+++ b/Core/sm83_cpu.c
@@ -658,8 +658,8 @@ static bool condition_code(GB_gameboy_t *gb, uint8_t opcode)
             return !(gb->af & GB_CARRY_FLAG);
         case 3:
             return (gb->af & GB_CARRY_FLAG);
+        nodefault;
     }
-    __builtin_unreachable();
 
     return false;
 }