turn into a Cargo crate

examples/crash.rs

@@ -0,0 +1,58 @@
+//! Debugging a crash (exception)
+//!
+//! The `cortex-m-rt` crate provides functionality for this through a default
+//! exception handler. When an exception is hit, the default handler will
+//! trigger a breakpoint and in this debugging context the stacked registers
+//! are accessible.
+//!
+//! In you run the example below, you'll be able to inspect the state of your
+//! program under the debugger using these commands:
+//!
+//! ```
+//! (gdb) # Stacked registers = program state during the crash
+//! (gdb) print/x *_sr
+//! $1 = cortex_m::exception::StackedRegisters {
+//!   r0 = 0x2fffffff,
+//!   r1 = 0x2fffffff,
+//!   r2 = 0x0,
+//!   r3 = 0x0,
+//!   r12 = 0x0,
+//!   lr = 0x8000443,
+//!   pc = 0x8000190,
+//!   xpsr = 0x61000200,
+//! }
+//!
+//! (gdb) # What exception was triggered?
+//! (gdb) print _e
+//! $2 = cortex_m::exception::Exception::HardFault
+//!
+//! (gdb) # Where did we come from?
+//! (gdb) print _e
+//! ```
+
+#![feature(used)]
+#![no_std]
+
+extern crate cortex_m;
+extern crate cortex_m_rt;
+
+use core::ptr;
+
+use cortex_m::asm;
+
+fn main() {
+    // Read an invalid memory address
+    unsafe {
+        ptr::read_volatile(0x2FFF_FFFF as *const u32);
+    }
+}
+
+// As we are not using interrupts, we just register a dummy catch all handler
+#[allow(dead_code)]
+#[used]
+#[link_section = ".rodata.interrupts"]
+static INTERRUPTS: [extern "C" fn(); 240] = [default_handler; 240];
+
+extern "C" fn default_handler() {
+    asm::bkpt();
+}