Adds an example to check critical-section works.

examples/mps3-an536/Cargo.toml

@@ -16,6 +16,7 @@ cortex-ar = { path = "../../cortex-ar", features = ["critical-section-single-cor
 cortex-r-rt = { path = "../../cortex-r-rt" }
 semihosting = { version = "0.1.18", features = ["stdio"] }
 arm-gic = { git = "https://github.com/google/arm-gic.git", rev = "46a8fc1720f5c28fccf4dfb5953b88dab7012e9c", optional = true }
+critical-section = "1.2.0"
 
 [build-dependencies]
 arm-targets = {version = "0.1.0", path = "../../arm-targets"}

examples/mps3-an536/src/bin/critical_section.rs

@@ -0,0 +1,38 @@
+//! critical-section example for Arm Cortex-R
+
+#![no_std]
+#![no_main]
+
+use core::cell::RefCell;
+
+// pull in our start-up code
+use mps3_an536 as _;
+
+use semihosting::println;
+
+struct Data {
+    value: u32
+}
+
+static GLOBAL_DATA: critical_section::Mutex<RefCell<Data>> = critical_section::Mutex::new(RefCell::new(Data { value: 100 }));
+
+/// The entry-point to the Rust application.
+///
+/// It is called by the start-up code in `cortex-m-rt`.
+#[no_mangle]
+pub extern "C" fn kmain() {
+    main();
+}
+
+/// The main function of our Rust application.
+///
+/// Called by [`kmain`].
+fn main() -> ! {
+    let value = critical_section::with(|cs| {
+        let mut data = GLOBAL_DATA.borrow_ref_mut(cs);
+        data.value += 1;
+        data.value
+    });
+    println!("Data is {}", value);
+    panic!("I am an example panic");
+}