Turbo and rewind speed controls

iOS/GBSettingsViewController.m

@@ -130,6 +130,22 @@ static NSString const *typeLightTemp = @"typeLightTemp";
                 @{@"type": typeRadio, @"pref": @"GBRTCMode", @"title": @"Sync to System Clock", @"value": @(GB_RTC_MODE_SYNC_TO_HOST),},
             ]
         },
+        @{
+            @"header": @"Turbo Speed",
+            @"items": @[
+                    @{@"type": typeRadio, @"pref": @"GBTurboSpeed", @"title": @"200%",     @"value": @2,},
+                    @{@"type": typeRadio, @"pref": @"GBTurboSpeed", @"title": @"400%",     @"value": @4,},
+                    @{@"type": typeRadio, @"pref": @"GBTurboSpeed", @"title": @"Uncapped", @"value": @1,},
+            ]
+        },
+        @{
+            @"header": @"Rewind Speed",
+            @"items": @[
+                    @{@"type": typeRadio, @"pref": @"GBRewindSpeed", @"title": @"100%", @"value": @1,},
+                    @{@"type": typeRadio, @"pref": @"GBRewindSpeed", @"title": @"200%", @"value": @2,},
+                    @{@"type": typeRadio, @"pref": @"GBRewindSpeed", @"title": @"400%", @"value": @4,},
+            ]
+        },
         @{
             @"header": @"Emulated Revisions",
             @"items": @[

iOS/GBViewController.m

@@ -708,7 +708,26 @@ static void rumbleCallback(GB_gameboy_t *gb, double amp)
     if (_runMode == GBRunModeRewindPaused) {
         [_audioClient stop];
     }
-    GB_set_turbo_mode(&_gb, runMode == GBRunModeTurbo, false);
+    
+    switch (_runMode) {
+        case GBRunModeNormal:
+        case GBRunModeRewindPaused:
+            GB_set_turbo_mode(&_gb, false, false);
+            GB_set_clock_multiplier(&_gb, 1.0);
+            break;
+        case GBRunModeTurbo: {
+            double multiplier = [[NSUserDefaults standardUserDefaults] doubleForKey:@"GBTurboSpeed"];
+            GB_set_turbo_mode(&_gb, multiplier == 1, false);
+            GB_set_clock_multiplier(&_gb, multiplier);
+            break;
+        }
+        case GBRunModeRewind: {
+            double multiplier = [[NSUserDefaults standardUserDefaults] doubleForKey:@"GBRewindSpeed"];
+            GB_set_turbo_mode(&_gb, false, false);
+            GB_set_clock_multiplier(&_gb, multiplier);
+            break;
+        }
+    }
 }
 
 - (AVCaptureDevice *)captureDevice

iOS/main.m

@@ -19,6 +19,8 @@ int main(int argc, char * argv[])
             @"GBSGBModel": @(GB_MODEL_SGB2),
             @"GBRumbleMode": @(GB_RUMBLE_CARTRIDGE_ONLY),
             @"GBButtonHaptics": @YES,
+            @"GBTurboSpeed": @1,
+            @"GBRewindSpeed": @1,
                         
             @"GBCurrentTheme": @"Lime (Game Boy)",
             // Default themes