ExceptionFrame: make fmt::Debug print address in hex

Author: japaric

cortex-m-rt/src/lib.rs

@@ -384,28 +384,58 @@
 
 extern crate r0;
 
+use core::fmt;
+
 /// Registers stacked (pushed into the stack) during an exception
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy)]
 #[repr(C)]
 pub struct ExceptionFrame {
     /// (General purpose) Register 0
     pub r0: u32,
+
     /// (General purpose) Register 1
     pub r1: u32,
+
     /// (General purpose) Register 2
     pub r2: u32,
+
     /// (General purpose) Register 3
     pub r3: u32,
+
     /// (General purpose) Register 12
     pub r12: u32,
+
     /// Linker Register
     pub lr: u32,
+
     /// Program Counter
     pub pc: u32,
+
     /// Program Status Register
     pub xpsr: u32,
 }
 
+impl fmt::Debug for ExceptionFrame {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        struct Hex(u32);
+        impl fmt::Debug for Hex {
+            fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+                write!(f, "0x{:08x}", self.0)
+            }
+        }
+        f.debug_struct("ExceptionFrame")
+            .field("r0", &Hex(self.r0))
+            .field("r1", &Hex(self.r1))
+            .field("r2", &Hex(self.r2))
+            .field("r3", &Hex(self.r3))
+            .field("r12", &Hex(self.r12))
+            .field("lr", &Hex(self.lr))
+            .field("pc", &Hex(self.pc))
+            .field("xpsr", &Hex(self.xpsr))
+            .finish()
+    }
+}
+
 /// Returns a pointer into which the heap can be placed
 ///
 /// The start of the heap is guaranteed to be 4-byte aligned; that is the pointer returned by this