//! Overriding an exception handler
//!
//! You can override an exception handler using the [`exception!`][1] macro.
//!
//! [1]: https://docs.rs/cortex-m-rt/0.3.2/cortex_m_rt/macro.exception.html
//!
//! The default exception handler can be overridden using the
//! [`default_handler!`][2] macro
//!
//! [2]: https://docs.rs/cortex-m-rt/0.3.2/cortex_m_rt/macro.default_handler.html
//!
//! ---

#![feature(used)]
#![no_std]

extern crate cortex_m;
#[macro_use(exception)]
extern crate cortex_m_rt;

use core::ptr;

use cortex_m::asm;

fn main() {
    unsafe {
        // Invalid memory access
        ptr::read_volatile(0x2FFF_FFFF as *const u32);
    }
}

exception!(HARD_FAULT, handler);

fn handler() {
    // You'll hit this breakpoint rather than the one in cortex-m-rt
    asm::bkpt()
}

// As we are not using interrupts, we just register a dummy catch all handler
#[allow(dead_code)]
#[used]
#[link_section = ".vector_table.interrupts"]
static INTERRUPTS: [extern "C" fn(); 240] = [default_handler; 240];

extern "C" fn default_handler() {
    asm::bkpt();
}