add CI, add device specific check of the vector table size, ..

- document the `main` symbol as an alternative to `entry!`
- document `ResetTrampoline`
- fix: `PendSV` is available on ARMv6-M
- document that `entry!` and `exception!` must be called from accessible modules.
- add a deny lint to `entry!` and `exception!` to prevent them from being invoked from inaccessible
  modules.

1 files changed, 38 insertions, 0 deletions

diff --git a/cortex-m-rt/examples/state.rs b/cortex-m-rt/examples/state.rs
new file mode 100644
index 0000000..0b5eeeb
--- /dev/null
+++ b/cortex-m-rt/examples/state.rs
@@ -0,0 +1,38 @@
+//! Preserving state across executions of an exception handler
+
+#![deny(unsafe_code)]
+#![deny(warnings)]
+#![no_main]
+#![no_std]
+
+#[macro_use(entry, exception)]
+extern crate cortex_m_rt as rt;
+extern crate panic_semihosting;
+
+use rt::ExceptionFrame;
+
+// the program entry point
+entry!(main);
+
+fn main() -> ! {
+    loop {}
+}
+
+// exception handler with state
+exception!(SysTick, sys_tick, state: u32 = 0);
+
+fn sys_tick(state: &mut u32) {
+    *state += 1;
+}
+
+// the hard fault handler
+exception!(HardFault, hard_fault);
+
+fn hard_fault(_ef: &ExceptionFrame) -> ! {
+    loop {}
+}
+
+// the default exception handler
+exception!(*, default_handler);
+
+fn default_handler(_irqn: i16) {}