Cargo.toml

@@ -16,8 +16,8 @@ rtt-target = { version = "0.3.0", features = ["cortex-m"] }
 
 # panic handlers
 panic-halt = "0.2.0"
-panic-semihosting = "0.5.6"
-panic-rtt-target = { version = "0.1.1", features = ["cortex-m"] }
+#panic-semihosting = "0.5.6"
+#panic-rtt-target = { version = "0.1.1", features = ["cortex-m"] }
 
 [dependencies.stm32f4]
 version = "0.12.1"

src/main.rs

@@ -5,8 +5,8 @@
 #![no_main]
 #![no_std]
 
-// use panic_halt as _;
-use panic_rtt_target as _;
+use panic_halt as _;
+//use panic_rtt_target as _;
 use rtt_target::{rprintln, rtt_init_print};
 use stm32f4;
 
@@ -21,10 +21,12 @@ const APP: () = {
     #[idle]
     fn idle(_cx: idle::Context) -> ! {
         rprintln!("idle");
-        // panic!("panic");
+        panic!("panic");
+        /*
         loop {
             continue;
         }
+        */
     }
 };
 
@@ -64,6 +66,16 @@ const APP: () = {
 // What is the output?
 //
 // [Your answer here]
+/*
+    Finished dev [unoptimized + debuginfo] target(s) in 0.03s
+     Running `probe-run --chip STM32F411RETx target/thumbv7em-none-eabi/debug/app`
+  (HOST) INFO  flashing program (18.18 KiB)
+  (HOST) INFO  success!
+────────────────────────────────────────────────────────────────────────────────
+init
+idle
+panicked at 'panic', src/main.rs:24:9
+*/
 //
 // D) Panic halt
 // Tracing is nice during development, but requires a debugger attached
@@ -77,12 +89,38 @@ const APP: () = {
 // What is the output?
 //
 // [Your answer here]
+/*
+    Finished dev [unoptimized + debuginfo] target(s) in 0.03s
+     Running `probe-run --chip STM32F411RETx target/thumbv7em-none-eabi/debug/app`
+  (HOST) INFO  flashing program (10.54 KiB)
+  (HOST) INFO  success!
+────────────────────────────────────────────────────────────────────────────────
+init
+idle
+*/
 //
 // Now press Ctrl-C
 //
 // What is the output?
 //
 // [Your answer here]
+/*
+^Cstack backtrace:
+   0: core::sync::atomic::compiler_fence
+        at /home/ironedde/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/sync/atomic.rs:2640
+   1: rust_begin_unwind
+        at /home/ironedde/.cargo/registry/src/github.com-1ecc6299db9ec823/panic-halt-0.2.0/src/lib.rs:33
+   2: core::panicking::panic_fmt
+        at /rustc/7eac88abb2e57e752f3302f02be5f3ce3d7adfb4/library/core/src/panicking.rs:85
+   3: core::panicking::panic
+        at /rustc/7eac88abb2e57e752f3302f02be5f3ce3d7adfb4/library/core/src/panicking.rs:50
+   4: app::idle
+        at src/main.rs:24
+   5: main
+        at src/main.rs:13
+   6: Reset
+        at /home/ironedde/.cargo/registry/src/github.com-1ecc6299db9ec823/cortex-m-rt-0.6.13/src/lib.rs:526
+*/
 //
 // E) Find the source
 // Figure out how to find the source of `panic_halt`, and look at the implementation.
@@ -92,3 +130,15 @@ const APP: () = {
 //
 // Paste the implementation here
 // [Your answer here]
+/*
+The implementation for our panic is found to be an infinite loop with a no reordering compiler fence.
+This means that it is impossible for the program to leave this point in the code. This is a halt. 
+
+#[inline(never)]
+#[panic_handler]
+fn panic(_info: &PanicInfo) -> ! {
+    loop {
+        atomic::compiler_fence(Ordering::SeqCst);
+    }
+}
+*/