diff --git a/Cargo.lock b/Cargo.lock
index ef0a2d9..d6c1786 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1413,6 +1413,7 @@ dependencies = [
  "jni",
  "log 0.4.11",
  "rustboyadvance-core",
+ "rustboyadvance-utils",
 ]
 
 [[package]]
@@ -1425,6 +1426,7 @@ dependencies = [
  "libretro-sys",
  "log 0.4.11",
  "rustboyadvance-core",
+ "rustboyadvance-utils",
  "unsafe_unwrap",
 ]
 
@@ -1472,6 +1474,7 @@ dependencies = [
  "js-sys",
  "log 0.4.11",
  "rustboyadvance-core",
+ "rustboyadvance-utils",
  "wasm-bindgen",
  "wasm-bindgen-console-logger",
  "wasm-bindgen-test",
diff --git a/arm7tdmi/build.rs b/arm7tdmi/build.rs
index d02b75c..33eeeae 100644
--- a/arm7tdmi/build.rs
+++ b/arm7tdmi/build.rs
@@ -265,7 +265,7 @@ fn arm_decode(i: u32) -> (&'static str, String) {
                 }
                 (0b010, 0b0001) => {
                     if 0b010 == i.bit_range(20..23) {
-                        Some(("BranchExchange", format!("exec_arm_bx")))
+                        Some(("BranchExchange", "exec_arm_bx".to_string()))
                     } else {
                         None
                     }
diff --git a/arm7tdmi/src/arm/exec.rs b/arm7tdmi/src/arm/exec.rs
index adf9d9f..72fd706 100644
--- a/arm7tdmi/src/arm/exec.rs
+++ b/arm7tdmi/src/arm/exec.rs
@@ -336,9 +336,7 @@ impl<I: MemoryInterface> Arm7tdmiCore<I> {
         }
 
         if !LOAD || base_reg != dest_reg {
-            if !PRE_INDEX {
-                self.set_reg(base_reg, effective_addr);
-            } else if WRITEBACK {
+            if !PRE_INDEX || WRITEBACK{
                 self.set_reg(base_reg, effective_addr);
             }
         }
diff --git a/core/src/cartridge/rtc.rs b/core/src/cartridge/rtc.rs
index 148fe79..309e33b 100644
--- a/core/src/cartridge/rtc.rs
+++ b/core/src/cartridge/rtc.rs
@@ -496,8 +496,6 @@ mod registers {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use std::cell::Cell;
-    use std::rc::Rc;
 
     fn transmit(rtc: &mut Rtc, gpio_state: &GpioState, bit: u8) {
         rtc.write(&gpio_state, 0b0100_u16 | (u16::from(bit) << 1));
@@ -617,7 +615,7 @@ mod tests {
         let mut bytes = [0];
         receive_bytes(&mut rtc, &gpio_state, &mut bytes);
 
-        let mut read_status = registers::StatusRegister(bytes[0]);
+        let read_status = registers::StatusRegister(bytes[0]);
         assert_eq!(read_status.mode_24h(), true);
     }
 
diff --git a/core/src/gpu/mod.rs b/core/src/gpu/mod.rs
index 36989cc..d65d46e 100644
--- a/core/src/gpu/mod.rs
+++ b/core/src/gpu/mod.rs
@@ -577,18 +577,18 @@ mod tests {
         macro_rules! update {
             ($cycles:expr) => {
                 sched.update($cycles);
-                let (event, cycles_late) = sched.pop_pending_event().unwrap();
-                assert_eq!(cycles_late, 0);
-                match event {
+                let (event, event_time) = sched.pop_pending_event().unwrap();
+                assert_eq!(event_time, sched.timestamp());
+                let next_event = match event {
                     EventType::Gpu(event) => gpu.on_event(
                         event,
-                        cycles_late,
                         &mut dma_notifier,
                         #[cfg(not(feature = "no_video_interface"))]
                         &video_clone,
                     ),
                     _ => panic!("Found unexpected event in queue!"),
-                }
+                };
+                sched.schedule(next_event);
             };
         }
 
diff --git a/core/src/sched.rs b/core/src/sched.rs
index 4ef031c..2cbff20 100644
--- a/core/src/sched.rs
+++ b/core/src/sched.rs
@@ -109,12 +109,15 @@ pub struct Scheduler {
 pub type SharedScheduler = Shared<Scheduler>;
 
 impl Scheduler {
-    pub fn new_shared() -> SharedScheduler {
-        let sched = Scheduler {
+    pub fn new() -> Scheduler {
+        Scheduler {
             timestamp: 0,
             events: BinaryHeap::with_capacity(NUM_EVENTS),
-        };
-        SharedScheduler::new(sched)
+        }
+    }
+
+    pub fn new_shared() -> SharedScheduler {
+        Scheduler::new().make_shared()
     }
 
     pub fn make_shared(self) -> SharedScheduler {
diff --git a/platform/rustboyadvance-jni/Cargo.toml b/platform/rustboyadvance-jni/Cargo.toml
index 33aba92..824e1d1 100644
--- a/platform/rustboyadvance-jni/Cargo.toml
+++ b/platform/rustboyadvance-jni/Cargo.toml
@@ -11,6 +11,7 @@ crate-type = ["staticlib", "cdylib"]
 
 [dependencies]
 rustboyadvance-core = {path = "../../core/", features = ["no_video_interface"]}
+rustboyadvance-utils = {path = "../../utils/" }
 jni = "0.17.0"
 log = {version = "0.4.8", features = ["release_max_level_info", "max_level_debug"]}
 
diff --git a/platform/rustboyadvance-jni/src/audio/thread.rs b/platform/rustboyadvance-jni/src/audio/thread.rs
index d2e1efa..6f042f0 100644
--- a/platform/rustboyadvance-jni/src/audio/thread.rs
+++ b/platform/rustboyadvance-jni/src/audio/thread.rs
@@ -4,7 +4,7 @@ use std::sync::mpsc::{channel, Sender};
 use std::thread;
 use std::thread::JoinHandle;
 
-use rustboyadvance_core::util::audio::Consumer;
+use rustboyadvance_utils::audio::Consumer;
 
 use jni::JavaVM;
 
diff --git a/platform/rustboyadvance-jni/src/emulator.rs b/platform/rustboyadvance-jni/src/emulator.rs
index 00a55ed..992f0c1 100644
--- a/platform/rustboyadvance-jni/src/emulator.rs
+++ b/platform/rustboyadvance-jni/src/emulator.rs
@@ -1,5 +1,5 @@
 use rustboyadvance_core::prelude::*;
-use rustboyadvance_core::util::audio::{AudioRingBuffer, Producer};
+use rustboyadvance_utils::audio::{AudioRingBuffer, Producer};
 // use rustboyadvance_core::util::FpsCounter;
 
 use std::cell::RefCell;
diff --git a/platform/rustboyadvance-jni/src/lib.rs b/platform/rustboyadvance-jni/src/lib.rs
index 9a8a955..a8f8d4d 100644
--- a/platform/rustboyadvance-jni/src/lib.rs
+++ b/platform/rustboyadvance-jni/src/lib.rs
@@ -289,7 +289,7 @@ pub mod bindings {
     pub unsafe extern "C" fn Java_com_mrmichel_rustboyadvance_EmulatorBindings_log(
         _env: JNIEnv,
         _obj: JClass,
-        ctx: jlong,
+        _ctx: jlong,
     ) {
         info!("unimplemented")
     }
diff --git a/platform/rustboyadvance-libretro/Cargo.toml b/platform/rustboyadvance-libretro/Cargo.toml
index bfca404..68e1002 100644
--- a/platform/rustboyadvance-libretro/Cargo.toml
+++ b/platform/rustboyadvance-libretro/Cargo.toml
@@ -11,6 +11,7 @@ crate-type = ["cdylib"]
 
 [dependencies]
 rustboyadvance-core = { path = "../../core/", features = ["no_video_interface"] }
+rustboyadvance-utils = { path = "../../utils" }
 log = "0.4.8"
 libc = "0.2"
 libretro-sys = "0.1.1"
diff --git a/platform/rustboyadvance-libretro/src/lib.rs b/platform/rustboyadvance-libretro/src/lib.rs
index 3201c3f..c5c75b9 100644
--- a/platform/rustboyadvance-libretro/src/lib.rs
+++ b/platform/rustboyadvance-libretro/src/lib.rs
@@ -13,7 +13,7 @@ use unsafe_unwrap::UnsafeUnwrap;
 
 use rustboyadvance_core::keypad::Keys as GbaButton;
 use rustboyadvance_core::prelude::*;
-use rustboyadvance_core::util::audio::AudioRingBuffer;
+use rustboyadvance_utils::audio::AudioRingBuffer;
 
 use std::path::Path;
 
@@ -115,7 +115,7 @@ impl libretro_backend::Core for RustBoyAdvanceCore {
 
                 let hwif = Rc::new(RefCell::new(HwInterface {
                     key_state: rustboyadvance_core::keypad::KEYINPUT_ALL_RELEASED,
-                    audio_ring_buffer: AudioRingBuffer::new(),
+                    audio_ring_buffer: Default::default(),
                 }));
                 let gba = GameBoyAdvance::new(
                     bios.into_boxed_slice(),
diff --git a/platform/rustboyadvance-sdl2/src/main.rs b/platform/rustboyadvance-sdl2/src/main.rs
index df17136..82604c1 100644
--- a/platform/rustboyadvance-sdl2/src/main.rs
+++ b/platform/rustboyadvance-sdl2/src/main.rs
@@ -48,6 +48,7 @@ use rustboyadvance_core::prelude::*;
 use rustboyadvance_utils::FpsCounter;
 
 const LOG_DIR: &str = ".logs";
+#[cfg(feature = "gdb")]
 const DEFAULT_GDB_SERVER_ADDR: &'static str = "localhost:1337";
 
 const CANVAS_WIDTH: u32 = SCREEN_WIDTH;
@@ -243,6 +244,10 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
     if with_gdbserver {
         spawn_and_run_gdb_server(&mut gba, DEFAULT_GDB_SERVER_ADDR)?;
     }
+    #[cfg(not(feature = "gdb"))]
+    if with_gdbserver {
+        panic!("Please compile me with 'gdb' feature")
+    }
 
     let mut fps_counter = FpsCounter::default();
     let frame_time = time::Duration::new(0, 1_000_000_000u32 / 60);
diff --git a/platform/rustboyadvance-wasm/Cargo.toml b/platform/rustboyadvance-wasm/Cargo.toml
index 72473b8..7efc3d2 100644
--- a/platform/rustboyadvance-wasm/Cargo.toml
+++ b/platform/rustboyadvance-wasm/Cargo.toml
@@ -14,6 +14,7 @@ default = ["console_error_panic_hook"]
 js-sys = "0.3.37"
 wasm-bindgen = "0.2"
 rustboyadvance-core = { path = "../../core" }
+rustboyadvance-utils = { path = "../../utils" }
 
 # The `console_error_panic_hook` crate provides better debugging of panics by
 # logging them with `console.error`. This is great for development, but requires
diff --git a/platform/rustboyadvance-wasm/src/emulator.rs b/platform/rustboyadvance-wasm/src/emulator.rs
index 5cbc959..b8c6ea5 100644
--- a/platform/rustboyadvance-wasm/src/emulator.rs
+++ b/platform/rustboyadvance-wasm/src/emulator.rs
@@ -11,7 +11,7 @@ use web_sys::CanvasRenderingContext2d;
 
 use rustboyadvance_core::keypad as gba_keypad;
 use rustboyadvance_core::prelude::*;
-use rustboyadvance_core::util::audio::AudioRingBuffer;
+use rustboyadvance_utils::audio::AudioRingBuffer;
 
 use bit::BitIndex;
 
@@ -42,7 +42,7 @@ impl Interface {
             keyinput: gba_keypad::KEYINPUT_ALL_RELEASED,
             sample_rate: audio_ctx.sample_rate() as i32,
             audio_ctx: audio_ctx,
-            audio_ring_buffer: AudioRingBuffer::new(),
+            audio_ring_buffer: Default::default(),
         })
     }
 }
@@ -61,7 +61,7 @@ impl VideoInterface for Interface {
 }
 
 fn convert_sample(s: i16) -> f32 {
-    ((s as f32) / 32767_f32)
+    (s as f32) / 32767_f32
 }
 
 impl AudioInterface for Interface {
@@ -156,7 +156,7 @@ impl Emulator {
     }
 
     pub fn test_fps(&mut self) {
-        use rustboyadvance_core::util::FpsCounter;
+        use rustboyadvance_utils::FpsCounter;
 
         let mut fps_counter = FpsCounter::default();
 
diff --git a/utils/src/lib.rs b/utils/src/lib.rs
index ab1747e..07927d3 100644
--- a/utils/src/lib.rs
+++ b/utils/src/lib.rs
@@ -29,7 +29,7 @@ pub fn read_bin_file(filename: &Path) -> io::Result<Vec<u8>> {
     Ok(buf)
 }
 
-pub fn write_bin_file(filename: &Path, data: &Vec<u8>) -> io::Result<()> {
+pub fn write_bin_file(filename: &Path, data: &[u8]) -> io::Result<()> {
     let mut f = File::create(filename)?;
     f.write_all(data)?;
 
@@ -94,11 +94,13 @@ pub mod audio {
         cons: Consumer<i16>,
     }
 
-    impl AudioRingBuffer {
-        pub fn new() -> AudioRingBuffer {
+    impl Default for AudioRingBuffer {
+        fn default() -> AudioRingBuffer {
             AudioRingBuffer::new_with_capacity(2 * 4096)
         }
+    }
 
+    impl AudioRingBuffer {
         pub fn new_with_capacity(capacity: usize) -> AudioRingBuffer {
             let rb = RingBuffer::new(capacity);
             let (prod, cons) = rb.split();
@@ -192,10 +194,6 @@ impl<T> Shared<T> {
     pub fn new(t: T) -> Shared<T> {
         Shared(Rc::new(UnsafeCell::new(t)))
     }
-
-    pub unsafe fn inner_unsafe(&self) -> &mut T {
-        &mut (*self.0.get())
-    }
 }
 
 impl<T> Shared<T>