update examples and docs

src/examples/_5_exception.rs

@@ -0,0 +1,73 @@
+//! Overriding an exception handler
+//!
+//! You can override an exception handler using the [`exception!`][1] macro.
+//!
+//! [1]: https://docs.rs/cortex-m-rt/0.5.0/cortex_m_rt/macro.exception.html
+//!
+//! ---
+//!
+//! ```
+//! 
+//! #![deny(unsafe_code)]
+//! #![no_main]
+//! #![no_std]
+//! 
+//! extern crate cortex_m;
+//! #[macro_use]
+//! extern crate cortex_m_rt as rt;
+//! extern crate cortex_m_semihosting as sh;
+//! extern crate panic_abort;
+//! 
+//! use core::fmt::Write;
+//! 
+//! use cortex_m::peripheral::syst::SystClkSource;
+//! use cortex_m::{asm, Peripherals};
+//! use rt::ExceptionFrame;
+//! use sh::hio::{self, HStdout};
+//! 
+//! main!(main);
+//! 
+//! fn main() -> ! {
+//!     let p = Peripherals::take().unwrap();
+//!     let mut syst = p.SYST;
+//! 
+//!     syst.set_clock_source(SystClkSource::Core);
+//!     syst.set_reload(8_000_000); // 1s
+//!     syst.enable_counter();
+//!     syst.enable_interrupt();
+//! 
+//!     loop {}
+//! }
+//! 
+//! // try commenting out this line: you'll end in `deh` instead of in `sys_tick`
+//! exception!(SysTick, sys_tick, state: Option<HStdout> = None);
+//! 
+//! fn sys_tick(state: &mut Option<HStdout>) {
+//!     if state.is_none() {
+//!         *state = Some(hio::hstdout().unwrap());
+//!     }
+//! 
+//!     if let Some(hstdout) = state.as_mut() {
+//!         hstdout.write_str(".").unwrap();
+//!     }
+//! }
+//! 
+//! exception!(DefaultHandler, deh);
+//! 
+//! #[inline(always)]
+//! fn deh(_nr: u8) {
+//!     asm::bkpt();
+//! }
+//! 
+//! exception!(HardFault, hf);
+//! 
+//! #[inline(always)]
+//! fn hf(_ef: &ExceptionFrame) -> ! {
+//!     asm::bkpt();
+//! 
+//!     loop {}
+//! }
+//! 
+//! interrupts!(DefaultHandler);
+//! ```
+// Auto-generated. Do not modify.