diff --git a/src/asm.rs b/src/asm.rs
index daa7b55d..aab772ef 100644
--- a/src/asm.rs
+++ b/src/asm.rs
@@ -7,58 +7,43 @@
 /// cause an exception
 #[inline(always)]
 pub fn bkpt() {
-    #[cfg(target_arch = "arm")]
-    unsafe {
-        asm!("bkpt"
-             :
-             :
-             :
-             : "volatile");
+    match () {
+        #[cfg(target_arch = "arm")]
+        () => unsafe { asm!("bkpt" :::: "volatile") },
+        #[cfg(not(target_arch = "arm"))]
+        () => unimplemented!(),
     }
 }
 
 /// A no-operation. Useful to prevent delay loops from being optimized away.
-#[inline(always)]
+#[inline]
 pub fn nop() {
-    unsafe {
-        asm!("nop"
-             :
-             :
-             :
-             : "volatile");
+    match () {
+        #[cfg(target_arch = "arm")]
+        () => unsafe { asm!("nop" :::: "volatile") },
+        #[cfg(not(target_arch = "arm"))]
+        () => unimplemented!(),
     }
 }
 /// Wait For Event
-#[inline(always)]
+#[inline]
 pub fn wfe() {
     match () {
         #[cfg(target_arch = "arm")]
-        () => unsafe {
-            asm!("wfe"
-                 :
-                 :
-                 :
-                 : "volatile")
-        },
+        () => unsafe { asm!("wfe" :::: "volatile") },
         #[cfg(not(target_arch = "arm"))]
-        () => {}
+        () => unimplemented!(),
     }
 }
 
 /// Wait For Interrupt
-#[inline(always)]
+#[inline]
 pub fn wfi() {
     match () {
         #[cfg(target_arch = "arm")]
-        () => unsafe{
-            asm!("wfi"
-                 :
-                 :
-                 :
-                 : "volatile")
-        },
+        () => unsafe { asm!("wfi" :::: "volatile") },
         #[cfg(not(target_arch = "arm"))]
-        () => {}
+        () => unimplemented!(),
     }
 }
 
@@ -66,15 +51,13 @@ pub fn wfi() {
 ///
 /// Flushes the pipeline in the processor, so that all instructions following the `ISB` are fetched
 /// from cache or memory, after the instruction has been completed.
-#[inline(always)]
+#[inline]
 pub fn isb() {
     match () {
         #[cfg(target_arch = "arm")]
-        () => unsafe {
-            asm!("isb 0xF" : : : "memory" : "volatile");
-        },
+        () => unsafe { asm!("isb 0xF" : : : "memory" : "volatile") },
         #[cfg(not(target_arch = "arm"))]
-        () => {}
+        () => unimplemented!(),
     }
 }
 
@@ -86,15 +69,13 @@ pub fn isb() {
 ///
 ///  * any explicit memory access made before this instruction is complete
 ///  * all cache and branch predictor maintenance operations before this instruction complete
-#[inline(always)]
+#[inline]
 pub fn dsb() {
     match () {
         #[cfg(target_arch = "arm")]
-        () => unsafe {
-            asm!("dsb 0xF" : : : "memory" : "volatile");
-        },
+        () => unsafe { asm!("dsb 0xF" : : : "memory" : "volatile") },
         #[cfg(not(target_arch = "arm"))]
-        () => {}
+        () => unimplemented!(),
     }
 }
 
@@ -103,14 +84,12 @@ pub fn dsb() {
 /// Ensures that all explicit memory accesses that appear in program order before the `DMB`
 /// instruction are observed before any explicit memory accesses that appear in program order
 /// after the `DMB` instruction.
-#[inline(always)]
+#[inline]
 pub fn dmb() {
     match () {
         #[cfg(target_arch = "arm")]
-        () => unsafe {
-            asm!("dmb 0xF" : : : "memory" : "volatile");
-        },
+        () => unsafe { asm!("dmb 0xF" : : : "memory" : "volatile") },
         #[cfg(not(target_arch = "arm"))]
-        () => {}
+        () => unimplemented!(),
     }
 }
diff --git a/src/interrupt.rs b/src/interrupt.rs
index de111250..5880dd4a 100644
--- a/src/interrupt.rs
+++ b/src/interrupt.rs
@@ -3,19 +3,15 @@
 pub use bare_metal::{CriticalSection, Mutex, Nr};
 
 /// Disables all interrupts
-#[inline(always)]
+#[inline]
 pub fn disable() {
     match () {
         #[cfg(target_arch = "arm")]
         () => unsafe {
-            asm!("cpsid i"
-                 :
-                 :
-                 : "memory"
-                 : "volatile");
+            asm!("cpsid i" ::: "memory" : "volatile");
         },
         #[cfg(not(target_arch = "arm"))]
-        () => {}
+        () => unimplemented!(),
     }
 }
 
@@ -24,19 +20,13 @@ pub fn disable() {
 /// # Safety
 ///
 /// - Do not call this function inside an `interrupt::free` critical section
-#[inline(always)]
+#[inline]
 pub unsafe fn enable() {
     match () {
         #[cfg(target_arch = "arm")]
-        () => {
-            asm!("cpsie i"
-                 :
-                 :
-                 : "memory"
-                 : "volatile");
-        }
+        () => asm!("cpsie i" ::: "memory" : "volatile"),
         #[cfg(not(target_arch = "arm"))]
-        () => {}
+        () => unimplemented!(),
     }
 }
 
diff --git a/src/peripheral/cbp.rs b/src/peripheral/cbp.rs
index 3397fff0..292ba043 100644
--- a/src/peripheral/cbp.rs
+++ b/src/peripheral/cbp.rs
@@ -35,7 +35,7 @@ const CBP_SW_SET_MASK: u32 = 0x1FF << CBP_SW_SET_POS;
 
 impl RegisterBlock {
     /// I-cache invalidate all to PoU
-    #[inline(always)]
+    #[inline]
     pub fn iciallu(&self) {
         unsafe {
             self.iciallu.write(0);
@@ -43,7 +43,7 @@ impl RegisterBlock {
     }
 
     /// I-cache invalidate by MVA to PoU
-    #[inline(always)]
+    #[inline]
     pub fn icimvau(&self, mva: u32) {
         unsafe {
             self.icimvau.write(mva);
@@ -51,7 +51,7 @@ impl RegisterBlock {
     }
 
     /// D-cache invalidate by MVA to PoC
-    #[inline(always)]
+    #[inline]
     pub fn dcimvac(&self, mva: u32) {
         unsafe {
             self.dcimvac.write(mva);
@@ -61,7 +61,7 @@ impl RegisterBlock {
     /// D-cache invalidate by set-way
     ///
     /// `set` is masked to be between 0 and 3, and `way` between 0 and 511.
-    #[inline(always)]
+    #[inline]
     pub fn dcisw(&self, set: u16, way: u16) {
         // The ARMv7-M Architecture Reference Manual, as of Revision E.b, says these set/way
         // operations have a register data format which depends on the implementation's
@@ -81,7 +81,7 @@ impl RegisterBlock {
     }
 
     /// D-cache clean by MVA to PoU
-    #[inline(always)]
+    #[inline]
     pub fn dccmvau(&self, mva: u32) {
         unsafe {
             self.dccmvau.write(mva);
@@ -89,7 +89,7 @@ impl RegisterBlock {
     }
 
     /// D-cache clean by MVA to PoC
-    #[inline(always)]
+    #[inline]
     pub fn dccmvac(&self, mva: u32) {
         unsafe {
             self.dccmvac.write(mva);
@@ -99,7 +99,7 @@ impl RegisterBlock {
     /// D-cache clean by set-way
     ///
     /// `set` is masked to be between 0 and 3, and `way` between 0 and 511.
-    #[inline(always)]
+    #[inline]
     pub fn dccsw(&self, set: u16, way: u16) {
         // See comment for dcisw() about the format here
         unsafe {
@@ -111,7 +111,7 @@ impl RegisterBlock {
     }
 
     /// D-cache clean and invalidate by MVA to PoC
-    #[inline(always)]
+    #[inline]
     pub fn dccimvac(&self, mva: u32) {
         unsafe {
             self.dccimvac.write(mva);
@@ -121,7 +121,7 @@ impl RegisterBlock {
     /// D-cache clean and invalidate by set-way
     ///
     /// `set` is masked to be between 0 and 3, and `way` between 0 and 511.
-    #[inline(always)]
+    #[inline]
     pub fn dccisw(&self, set: u16, way: u16) {
         // See comment for dcisw() about the format here
         unsafe {
@@ -133,7 +133,7 @@ impl RegisterBlock {
     }
 
     /// Branch predictor invalidate all
-    #[inline(always)]
+    #[inline]
     pub fn bpiall(&self) {
         unsafe {
             self.bpiall.write(0);
diff --git a/src/peripheral/mod.rs b/src/peripheral/mod.rs
index dbe3e352..d462bdb2 100644
--- a/src/peripheral/mod.rs
+++ b/src/peripheral/mod.rs
@@ -69,7 +69,7 @@ static mut CORE_PERIPHERALS: bool = false;
 
 impl Peripherals {
     /// Returns all the core peripherals *once*
-    #[inline(always)]
+    #[inline]
     pub fn take() -> Option<Self> {
         interrupt::free(|_| {
             if unsafe { CORE_PERIPHERALS } {
diff --git a/src/register/apsr.rs b/src/register/apsr.rs
index d966de0d..60dd3646 100644
--- a/src/register/apsr.rs
+++ b/src/register/apsr.rs
@@ -39,15 +39,18 @@ impl Apsr {
 }
 
 /// Reads the CPU register
-#[inline(always)]
+#[inline]
 pub fn read() -> Apsr {
-    let r: u32;
-    unsafe {
-        asm!("mrs $0, APSR"
-             : "=r"(r)
-             :
-             :
-             : "volatile");
+    match () {
+        #[cfg(target_arch = "arm")]
+        () => {
+            let r: u32;
+            unsafe {
+                asm!("mrs $0, APSR" : "=r"(r) ::: "volatile");
+            }
+            Apsr { bits: r }
+        }
+        #[cfg(not(target_arch = "arm"))]
+        () => unimplemented!(),
     }
-    Apsr { bits: r }
 }
diff --git a/src/register/basepri.rs b/src/register/basepri.rs
index c02fe843..a024d74c 100644
--- a/src/register/basepri.rs
+++ b/src/register/basepri.rs
@@ -1,25 +1,29 @@
 //! Base Priority Mask Register
 
 /// Reads the CPU register
-#[inline(always)]
+#[inline]
 pub fn read() -> u8 {
-    let r: u32;
-    unsafe {
-        asm!("mrs $0, BASEPRI"
-             : "=r"(r)
-             :
-             :
-             : "volatile");
+    match () {
+        #[cfg(target_arch = "arm")]
+        () => {
+            let r: u32;
+            unsafe {
+                asm!("mrs $0, BASEPRI" : "=r"(r) ::: "volatile");
+            }
+            r as u8
+        }
+        #[cfg(not(target_arch = "arm"))]
+        () => unimplemented!(),
     }
-    r as u8
 }
 
 /// Writes to the CPU register
-#[inline(always)]
-pub unsafe fn write(basepri: u8) {
-    asm!("msr BASEPRI, $0"
-         :
-         : "r"(basepri)
-         : "memory"
-         : "volatile");
+#[inline]
+pub unsafe fn write(_basepri: u8) {
+    match () {
+        #[cfg(target_arch = "arm")]
+        () => asm!("msr BASEPRI, $0" :: "r"(_basepri) : "memory" : "volatile"),
+        #[cfg(not(target_arch = "arm"))]
+        () => unimplemented!(),
+    }
 }
diff --git a/src/register/basepri_max.rs b/src/register/basepri_max.rs
index bcc7cdbb..0833aa7a 100644
--- a/src/register/basepri_max.rs
+++ b/src/register/basepri_max.rs
@@ -4,13 +4,14 @@
 ///
 /// - `basepri != 0` AND `basepri::read() == 0`, OR
 /// - `basepri != 0` AND `basepri < basepri::read()`
-#[inline(always)]
-pub fn write(basepri: u8) {
-    unsafe {
-        asm!("msr BASEPRI_MAX, $0"
-             :
-             : "r"(basepri)
-             : "memory"
-             : "volatile");
+#[inline]
+pub fn write(_basepri: u8) {
+    match () {
+        #[cfg(target_arch = "arm")]
+        () => unsafe {
+            asm!("msr BASEPRI_MAX, $0" :: "r"(_basepri) : "memory" : "volatile");
+        },
+        #[cfg(not(target_arch = "arm"))]
+        () => unimplemented!(),
     }
 }
diff --git a/src/register/control.rs b/src/register/control.rs
index d5cb8ec8..93c497fc 100644
--- a/src/register/control.rs
+++ b/src/register/control.rs
@@ -104,15 +104,16 @@ impl Fpca {
 }
 
 /// Reads the CPU register
-#[inline(always)]
+#[inline]
 pub fn read() -> Control {
-    let r: u32;
-    unsafe {
-        asm!("mrs $0, CONTROL"
-             : "=r"(r)
-             :
-             :
-             : "volatile");
+    match () {
+        #[cfg(target_arch = "arm")]
+        () => {
+            let r: u32;
+            unsafe { asm!("mrs $0, CONTROL" : "=r"(r) ::: "volatile") }
+            Control { bits: r }
+        }
+        #[cfg(not(target_arch = "arm"))]
+        () => unimplemented!(),
     }
-    Control { bits: r }
 }
diff --git a/src/register/faultmask.rs b/src/register/faultmask.rs
index 7a0d06c5..3e0980ef 100644
--- a/src/register/faultmask.rs
+++ b/src/register/faultmask.rs
@@ -22,19 +22,20 @@ impl Faultmask {
 }
 
 /// Reads the CPU register
-#[inline(always)]
+#[inline]
 pub fn read() -> Faultmask {
-    let r: u32;
-    unsafe {
-        asm!("mrs $0, FAULTMASK"
-             : "=r"(r)
-             :
-             :
-             : "volatile");
-    }
-    if r & (1 << 0) == (1 << 0) {
-        Faultmask::Inactive
-    } else {
-        Faultmask::Active
+    match () {
+        #[cfg(target_arch = "arm")]
+        () => {
+            let r: u32;
+            unsafe { asm!("mrs $0, FAULTMASK" : "=r"(r) ::: "volatile") }
+            if r & (1 << 0) == (1 << 0) {
+                Faultmask::Inactive
+            } else {
+                Faultmask::Active
+            }
+        }
+        #[cfg(not(target_arch = "arm"))]
+        () => unimplemented!(),
     }
 }
diff --git a/src/register/lr.rs b/src/register/lr.rs
index fecfecbe..ddbc07de 100644
--- a/src/register/lr.rs
+++ b/src/register/lr.rs
@@ -1,25 +1,28 @@
 //! Link register
 
 /// Reads the CPU register
-#[inline(always)]
+#[inline]
 pub fn read() -> u32 {
-    let r: u32;
-    unsafe {
-        asm!("mov $0,R14"
-             : "=r"(r)
-             :
-             :
-             : "volatile");
+    match () {
+        #[cfg(target_arch = "arm")]
+        () => {
+            let r: u32;
+            unsafe { asm!("mov $0,R14" : "=r"(r) ::: "volatile") }
+            r
+        }
+        #[cfg(not(target_arch = "arm"))]
+        () => unimplemented!(),
     }
-    r
 }
 
 /// Writes `bits` to the CPU register
-#[inline(always)]
+#[cfg_attr(not(target_arch = "arm"), allow(unused_variables))]
+#[inline]
 pub unsafe fn write(bits: u32) {
-    asm!("mov R14,$0"
-         :
-         : "r"(bits)
-         :
-         : "volatile");
+    match () {
+        #[cfg(target_arch = "arm")]
+        () => asm!("mov R14,$0" :: "r"(bits) :: "volatile"),
+        #[cfg(not(target_arch = "arm"))]
+        () => unimplemented!(),
+    }
 }
diff --git a/src/register/msp.rs b/src/register/msp.rs
index ebea6ed5..3b83353c 100644
--- a/src/register/msp.rs
+++ b/src/register/msp.rs
@@ -1,25 +1,28 @@
 //! Main Stack Pointer
 
 /// Reads the CPU register
-#[inline(always)]
+#[inline]
 pub fn read() -> u32 {
-    let r;
-    unsafe {
-        asm!("mrs $0,MSP"
-             : "=r"(r)
-             :
-             :
-             : "volatile");
+    match () {
+        #[cfg(target_arch = "arm")]
+        () => {
+            let r;
+            unsafe { asm!("mrs $0,MSP" : "=r"(r) ::: "volatile") }
+            r
+        }
+        #[cfg(not(target_arch = "arm"))]
+        () => unimplemented!(),
     }
-    r
 }
 
 /// Writes `bits` to the CPU register
-#[inline(always)]
+#[cfg_attr(not(target_arch = "arm"), allow(unused_variables))]
+#[inline]
 pub unsafe fn write(bits: u32) {
-    asm!("msr MSP,$0"
-         :
-         : "r"(bits)
-         :
-         : "volatile");
+    match () {
+        #[cfg(target_arch = "arm")]
+        () => asm!("msr MSP,$0" :: "r"(bits) :: "volatile"),
+        #[cfg(not(target_arch = "arm"))]
+        () => unimplemented!(),
+    }
 }
diff --git a/src/register/pc.rs b/src/register/pc.rs
index 3fec1aeb..7a7ef19a 100644
--- a/src/register/pc.rs
+++ b/src/register/pc.rs
@@ -1,25 +1,28 @@
 //! Program counter
 
 /// Reads the CPU register
-#[inline(always)]
+#[inline]
 pub fn read() -> u32 {
-    let r;
-    unsafe {
-        asm!("mov $0,R15"
-             : "=r"(r)
-             :
-             :
-             : "volatile");
+    match () {
+        #[cfg(target_arch = "arm")]
+        () => {
+            let r;
+            unsafe { asm!("mov $0,R15" : "=r"(r) ::: "volatile") }
+            r
+        }
+        #[cfg(not(target_arch = "arm"))]
+        () => unimplemented!(),
     }
-    r
 }
 
 /// Writes `bits` to the CPU register
-#[inline(always)]
+#[cfg_attr(not(target_arch = "arm"), allow(unused_variables))]
+#[inline]
 pub unsafe fn write(bits: u32) {
-    asm!("mov R15,$0"
-         :
-         : "r"(bits)
-         :
-         : "volatile");
+    match () {
+        #[cfg(target_arch = "arm")]
+        () => asm!("mov R15,$0" :: "r"(bits) :: "volatile"),
+        #[cfg(not(target_arch = "arm"))]
+        () => unimplemented!(),
+    }
 }
diff --git a/src/register/primask.rs b/src/register/primask.rs
index 313693f3..c9dc39a6 100644
--- a/src/register/primask.rs
+++ b/src/register/primask.rs
@@ -22,19 +22,20 @@ impl Primask {
 }
 
 /// Reads the CPU register
-#[inline(always)]
+#[inline]
 pub fn read() -> Primask {
-    let r: u32;
-    unsafe {
-        asm!("mrs $0, PRIMASK"
-             : "=r"(r)
-             :
-             :
-             : "volatile");
-    }
-    if r & (1 << 0) == (1 << 0) {
-        Primask::Inactive
-    } else {
-        Primask::Active
+    match () {
+        #[cfg(target_arch = "arm")]
+        () => {
+            let r: u32;
+            unsafe { asm!("mrs $0, PRIMASK" : "=r"(r) ::: "volatile") }
+            if r & (1 << 0) == (1 << 0) {
+                Primask::Inactive
+            } else {
+                Primask::Active
+            }
+        }
+        #[cfg(not(target_arch = "arm"))]
+        () => unimplemented!(),
     }
 }
diff --git a/src/register/psp.rs b/src/register/psp.rs
index ecd6f9cb..d7232db7 100644
--- a/src/register/psp.rs
+++ b/src/register/psp.rs
@@ -1,25 +1,28 @@
 //! Process Stack Pointer
 
 /// Reads the CPU register
-#[inline(always)]
+#[inline]
 pub fn read() -> u32 {
-    let r;
-    unsafe {
-        asm!("mrs $0,PSP"
-             : "=r"(r)
-             :
-             :
-             : "volatile");
+    match () {
+        #[cfg(target_arch = "arm")]
+        () => {
+            let r;
+            unsafe { asm!("mrs $0,PSP" : "=r"(r) ::: "volatile") }
+            r
+        }
+        #[cfg(not(target_arch = "arm"))]
+        () => unimplemented!(),
     }
-    r
 }
 
 /// Writes `bits` to the CPU register
-#[inline(always)]
+#[cfg_attr(not(target_arch = "arm"), allow(unused_variables))]
+#[inline]
 pub unsafe fn write(bits: u32) {
-    asm!("msr PSP,$0"
-         :
-         : "r"(bits)
-         :
-         : "volatile");
+    match () {
+        #[cfg(target_arch = "arm")]
+        () => asm!("msr PSP,$0" :: "r"(bits) :: "volatile"),
+        #[cfg(not(target_arch = "arm"))]
+        () => unimplemented!(),
+    }
 }