drop linker-flavor, port more examples

examples/exception.rs

@@ -0,0 +1,69 @@
+//! 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);