allow returns from checked::Resource.lock{,mut}

also add compiler barriers

1 files changed, 14 insertions, 0 deletions

diff --git a/src/lib.rs b/src/lib.rs
index 95aa8ba..7cd0ff6 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -105,7 +105,9 @@ where
     lock_check(ceiling);
     let old_basepri = basepri::read();
     basepri_max::write(ceiling);
+    compiler_barrier();
     let ret = f(&*res, ptr::read(0 as *const _));
+    compiler_barrier();
     basepri::write(old_basepri);
     ret
 }
@@ -121,11 +123,23 @@ where
     lock_check(ceiling);
     let old_basepri = basepri::read();
     basepri_max::write(ceiling);
+    compiler_barrier();
     let ret = f(&mut *res, ptr::read(0 as *const _));
+    compiler_barrier();
     basepri::write(old_basepri);
     ret
 }
 
+fn compiler_barrier() {
+    unsafe {
+        asm!(""
+             :
+             :
+             : "memory"
+             : "volatile");
+    }
+}
+
 /// A peripheral as a resource
 pub struct ResourceP<P, Ceiling>
 where