Merge #201

201: Add UDF instruction. Closes #199. r=jonas-schievink a=adamgreig



Co-authored-by: Adam Greig <adam@adamgreig.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/src/asm.rs b/src/asm.rs
index 3d84341..b7ff19e 100644
--- a/src/asm.rs
+++ b/src/asm.rs
@@ -81,6 +81,35 @@ pub fn nop() {
     }
 }
 
+
+/// Generate an Undefined Instruction exception.
+///
+/// Can be used as a stable alternative to `core::intrinsics::abort`.
+#[inline]
+pub fn udf() -> ! {
+    match () {
+        #[cfg(all(cortex_m, feature = "inline-asm"))]
+        () => unsafe {
+            asm!("udf" :::: "volatile");
+            core::hint::unreachable_unchecked();
+        },
+
+        #[cfg(all(cortex_m, not(feature = "inline-asm")))]
+        () => unsafe {
+            extern "C" {
+                fn __udf();
+            }
+
+            __udf();
+
+            core::hint::unreachable_unchecked();
+        },
+
+        #[cfg(not(cortex_m))]
+        () => unimplemented!(),
+    }
+}
+
 /// Wait For Event
 #[inline]
 pub fn wfe() {