cortex-m-quickstart 0.1.2

//! Overriding an exception
//!
//! **NOTE** You have to disable the `cortex-m-rt` crate's "exceptions" feature
//! to make this work.

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

extern crate cortex_m;
extern crate cortex_m_rt;

use core::ptr;

use cortex_m::{asm, exception};

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

extern "C" fn hard_fault(_: exception::HardFault) {
    // You'll hit this breakpoint rather than the one in cortex-m-rt
    asm::bkpt()
}

// When the "exceptions" feature is disabled, you'll have to provide this symbol
#[allow(dead_code)]
#[used]
#[link_section = ".rodata.exceptions"]
static EXCEPTIONS: exception::Handlers = exception::Handlers {
    // This is the exception handler override
    hard_fault: hard_fault,
    ..exception::DEFAULT_HANDLERS
};

// 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();
}