pub interface to logical2hw and hw2logical

1 files changed, 57 insertions, 93 deletions

diff --git a/src/lib.rs b/src/lib.rs
index ba5e0dc7..a2087860 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -47,8 +47,7 @@ pub struct Resource<T, CEILING> {
 impl<T, C> Resource<T, C> {
     /// Creates a new resource with ceiling `C`
     pub const fn new(data: T) -> Self
-    where
-        C: Ceiling,
+        where C: Ceiling
     {
         Resource {
             _ceiling: PhantomData,
@@ -62,14 +61,12 @@ impl<T, CEILING> Resource<T, C<CEILING>> {
     /// section
     ///
     /// This operation is zero cost and doesn't impose any additional blocking
-    pub fn borrow<'cs, PRIORITY, SCEILING>(
-        &'static self,
-        _priority: &P<PRIORITY>,
-        _system_ceiling: &'cs C<SCEILING>,
-    ) -> Ref<'cs, T>
-    where
-        SCEILING: GreaterThanOrEqual<CEILING>,
-        CEILING: GreaterThanOrEqual<PRIORITY>,
+    pub fn borrow<'cs, PRIORITY, SCEILING>(&'static self,
+                                           _priority: &P<PRIORITY>,
+                                           _system_ceiling: &'cs C<SCEILING>)
+                                           -> Ref<'cs, T>
+        where SCEILING: GreaterThanOrEqual<CEILING>,
+              CEILING: GreaterThanOrEqual<PRIORITY>
     {
         unsafe { Ref::new(&*self.data.get()) }
     }
@@ -77,24 +74,18 @@ impl<T, CEILING> Resource<T, C<CEILING>> {
     /// Claims the resource at the task with highest priority
     ///
     /// This operation is zero cost and doesn't impose any additional blocking
-    pub fn claim<'task, PRIORITY>(
-        &'static self,
-        _priority: &'task P<PRIORITY>,
-    ) -> Ref<'task, T>
-    where
-        CEILING: Cmp<PRIORITY, Output = Equal>,
+    pub fn claim<'task, PRIORITY>(&'static self, _priority: &'task P<PRIORITY>) -> Ref<'task, T>
+        where CEILING: Cmp<PRIORITY, Output = Equal>
     {
         unsafe { Ref::new(&*self.data.get()) }
     }
 
     /// Like [Resource.claim](struct.Resource.html#method.claim) but returns a
     /// `&mut-` reference
-    pub fn claim_mut<'task, PRIORITY>(
-        &'static self,
-        _priority: &'task mut P<PRIORITY>,
-    ) -> RefMut<'task, T>
-    where
-        CEILING: Cmp<PRIORITY, Output = Equal>,
+    pub fn claim_mut<'task, PRIORITY>(&'static self,
+                                      _priority: &'task mut P<PRIORITY>)
+                                      -> RefMut<'task, T>
+        where CEILING: Cmp<PRIORITY, Output = Equal>
     {
         unsafe { RefMut::new(&mut *self.data.get()) }
     }
@@ -109,22 +100,15 @@ impl<T, CEILING> Resource<T, C<CEILING>> {
     /// than `CEILING` can be borrowed at zero cost. See
     /// [Resource.borrow](struct.Resource.html#method.borrow).
     #[cfg(not(thumbv6m))]
-    pub fn lock<R, PRIORITY, F>(
-        &'static self,
-        _priority: &P<PRIORITY>,
-        f: F,
-    ) -> R
-    where
-        F: FnOnce(Ref<T>, C<CEILING>) -> R,
-        CEILING: Cmp<PRIORITY, Output = Greater> + Cmp<UMAX, Output = Less>
-            + Level,
+    pub fn lock<R, PRIORITY, F>(&'static self, _priority: &P<PRIORITY>, f: F) -> R
+        where F: FnOnce(Ref<T>, C<CEILING>) -> R,
+              CEILING: Cmp<PRIORITY, Output = Greater> + Cmp<UMAX, Output = Less> + Level
     {
         unsafe {
             let old_basepri = basepri::read();
             basepri_max::write(<CEILING>::hw());
             barrier!();
-            let ret =
-                f(Ref::new(&*self.data.get()), C { _marker: PhantomData });
+            let ret = f(Ref::new(&*self.data.get()), C { _marker: PhantomData });
             barrier!();
             basepri::write(old_basepri);
             ret
@@ -138,15 +122,9 @@ impl<T, CEILING> Resource<T, C<CEILING>> {
     /// resource that has ceiling equal `CEILING`. This constraint is required
     /// to preserve Rust aliasing rules.
     #[cfg(not(thumbv6m))]
-    pub fn lock_mut<R, PRIORITY, F>(
-        &'static self,
-        _priority: &mut P<PRIORITY>,
-        f: F,
-    ) -> R
-    where
-        F: FnOnce(RefMut<T>) -> R,
-        CEILING: Cmp<PRIORITY, Output = Greater> + Cmp<UMAX, Output = Less>
-            + Level,
+    pub fn lock_mut<R, PRIORITY, F>(&'static self, _priority: &mut P<PRIORITY>, f: F) -> R
+        where F: FnOnce(RefMut<T>) -> R,
+              CEILING: Cmp<PRIORITY, Output = Greater> + Cmp<UMAX, Output = Less> + Level
     {
         unsafe {
             let old_basepri = basepri::read();
@@ -160,32 +138,25 @@ impl<T, CEILING> Resource<T, C<CEILING>> {
     }
 }
 
-unsafe impl<T, C> Sync for Resource<T, C>
-where
-    C: Ceiling,
-{
-}
+unsafe impl<T, C> Sync for Resource<T, C> where C: Ceiling {}
 
 /// A hardware peripheral as a resource
 pub struct Peripheral<P, CEILING>
-where
-    P: 'static,
+    where P: 'static
 {
     peripheral: cortex_m::peripheral::Peripheral<P>,
     _ceiling: PhantomData<CEILING>,
 }
 
 impl<P, C> Peripheral<P, C>
-where
-    C: Ceiling,
+    where C: Ceiling
 {
     /// Assigns a ceiling `C` to the `peripheral`
     ///
     /// # Safety
     ///
     /// You MUST not create two resources that point to the same peripheral
-    pub const unsafe fn new(peripheral: cortex_m::peripheral::Peripheral<P>,)
-        -> Self {
+    pub const unsafe fn new(peripheral: cortex_m::peripheral::Peripheral<P>) -> Self {
         Peripheral {
             _ceiling: PhantomData,
             peripheral: peripheral,
@@ -195,49 +166,37 @@ where
 
 impl<Periph, CEILING> Peripheral<Periph, C<CEILING>> {
     /// See [Resource.borrow](./struct.Resource.html#method.borrow)
-    pub fn borrow<'cs, PRIORITY, SCEILING>(
-        &'static self,
-        _priority: &P<PRIORITY>,
-        _system_ceiling: &'cs C<SCEILING>,
-    ) -> Ref<'cs, Periph>
-    where
-        SCEILING: GreaterThanOrEqual<CEILING>,
-        CEILING: GreaterThanOrEqual<PRIORITY>,
+    pub fn borrow<'cs, PRIORITY, SCEILING>(&'static self,
+                                           _priority: &P<PRIORITY>,
+                                           _system_ceiling: &'cs C<SCEILING>)
+                                           -> Ref<'cs, Periph>
+        where SCEILING: GreaterThanOrEqual<CEILING>,
+              CEILING: GreaterThanOrEqual<PRIORITY>
     {
         unsafe { Ref::new(&*self.peripheral.get()) }
     }
 
     /// See [Resource.claim](./struct.Resource.html#method.claim)
-    pub fn claim<'task, PRIORITY>(
-        &'static self,
-        _priority: &'task P<PRIORITY>,
-    ) -> Ref<'task, Periph>
-    where
-        CEILING: Cmp<PRIORITY, Output = Equal>,
+    pub fn claim<'task, PRIORITY>(&'static self,
+                                  _priority: &'task P<PRIORITY>)
+                                  -> Ref<'task, Periph>
+        where CEILING: Cmp<PRIORITY, Output = Equal>
     {
         unsafe { Ref::new(&*self.peripheral.get()) }
     }
 
     /// See [Resource.lock](./struct.Resource.html#method.lock)
     #[cfg(not(thumbv6m))]
-    pub fn lock<R, PRIORITY, F>(
-        &'static self,
-        _priority: &P<PRIORITY>,
-        f: F,
-    ) -> R
-    where
-        F: FnOnce(Ref<Periph>, C<CEILING>) -> R,
-        CEILING: Cmp<PRIORITY, Output = Greater> + Cmp<UMAX, Output = Less>
-            + Level,
+    pub fn lock<R, PRIORITY, F>(&'static self, _priority: &P<PRIORITY>, f: F) -> R
+        where F: FnOnce(Ref<Periph>, C<CEILING>) -> R,
+              CEILING: Cmp<PRIORITY, Output = Greater> + Cmp<UMAX, Output = Less> + Level
     {
         unsafe {
             let old_basepri = basepri::read();
             basepri_max::write(<CEILING>::hw());
             barrier!();
-            let ret = f(
-                Ref::new(&*self.peripheral.get()),
-                C { _marker: PhantomData },
-            );
+            let ret = f(Ref::new(&*self.peripheral.get()),
+                        C { _marker: PhantomData });
             barrier!();
             basepri::write(old_basepri);
             ret
@@ -245,18 +204,13 @@ impl<Periph, CEILING> Peripheral<Periph, C<CEILING>> {
     }
 }
 
-unsafe impl<T, C> Sync for Peripheral<T, C>
-where
-    C: Ceiling,
-{
-}
+unsafe impl<T, C> Sync for Peripheral<T, C> where C: Ceiling {}
 
 /// A global critical section
 ///
 /// No task can preempt this critical section
 pub fn critical<R, F>(f: F) -> R
-where
-    F: FnOnce(CMAX) -> R,
+    where F: FnOnce(CMAX) -> R
 {
     let primask = ::cortex_m::register::primask::read();
     ::cortex_m::interrupt::disable();
@@ -274,9 +228,8 @@ where
 
 /// Requests the execution of a `task`
 pub fn request<T, P>(_task: fn(T, P))
-where
-    T: Context + Nr,
-    P: Priority,
+    where T: Context + Nr,
+          P: Priority
 {
     let nvic = unsafe { &*NVIC.get() };
 
@@ -310,8 +263,7 @@ pub struct P<T> {
 }
 
 impl<T> P<T>
-where
-    T: Level,
+    where T: Level
 {
     #[doc(hidden)]
     pub fn hw() -> u8 {
@@ -342,10 +294,22 @@ pub unsafe trait Level {
 /// DO NOT IMPLEMENT THIS TRAIT YOURSELF
 pub unsafe trait Priority {}
 
-fn logical2hw(logical: u8) -> u8 {
+
+/// Convert a logical priority to a shifted hardware prio
+/// as used by the NVIC and basepri registers
+/// Notice, wrapping causes a panic due to u8
+pub fn logical2hw(logical: u8) -> u8 {
     ((1 << PRIORITY_BITS) - logical) << (8 - PRIORITY_BITS)
 }
 
+/// Convert a shifted hardware prio to a logical priority
+/// as used by the NVIC and basepri registers
+/// Notice, wrapping causes a panic due to u8
+pub fn hw2logical(hw: u8) -> u8 {
+    (1 << PRIORITY_BITS) - (hw >> (8 - PRIORITY_BITS))
+}
+
+
 /// Priority 0, the lowest priority
 pub type P0 = P<::typenum::U0>;