refactor: move exception handler to new module

src/hardfaults.rs

@@ -0,0 +1,39 @@
+use cortex_m_rt::ExceptionFrame;
+
+fn display_ef(ef: &ExceptionFrame) {
+    struct Wrapper(ExceptionFrame);
+    impl defmt::Format for Wrapper {
+        fn format(&self, fmt: defmt::Formatter) {
+            defmt::write!(
+                fmt,
+                "ExceptionFrame(\n\tr0: {:08x}\n\tr1: {:08x}\n\tr2: {:08x}\n\tr3: {:08x}\n\tr12: {:08x}\n\tlr: {:08x}\n\tpc: {:08x}\n\txpsr: {:08x}\n)",
+                self.0.r0(),
+                self.0.r1(),
+                self.0.r2(),
+                self.0.r3(),
+                self.0.r12(),
+                self.0.lr(),
+                self.0.pc(),
+                self.0.xpsr()
+            );
+        }
+    }
+
+    error!("HardFault: Exception occured!");
+    error!("Exception occured at: {:08x}", ef.pc());
+    error!("XSPR: {:032b}", ef.xpsr());
+    error!("LR: {:08x}", ef.lr());
+
+    error!("HardFault: {:#?}", Wrapper(*ef))
+}
+
+#[allow(unreachable_code)]
+#[cortex_m_rt::exception(trampoline = true)]
+unsafe fn HardFault(ef: &ExceptionFrame) -> ! {
+    static mut EXCEPTION: Option<ExceptionFrame> = None;
+    unsafe { EXCEPTION = Some(*ef) };
+
+    display_ef(ef);
+    #[allow(clippy::empty_loop)]
+    loop {}
+}

src/main.rs

@@ -11,6 +11,8 @@ use defmt_rtt as _; // global logger
 use cortex_m_rt::{ExceptionFrame, entry};
 use hal::{pac, prelude::*, rcc::Config};
 
+mod hardfaults; // defines a handler for evil hardfaults
+
 // same panicking *behavior* as `panic-probe` but doesn't print a panic message
 // this prevents the panic message being printed *twice* when `defmt::panic` is invoked
 #[defmt::panic_handler]
@@ -38,7 +40,6 @@ fn main() -> ! {
     // Get the delay provider.
     let mut delay = cp.SYST.delay(rcc.clocks);
 
-    // BUG: this program seems to completely halt whenever a C function is called.
     debug!("Asserting that libalgorithms is correctly loaded");
     assert!(algorithms::ffi_is_loaded(), "ffi is not loaded?");
 
@@ -62,41 +63,3 @@ fn main() -> ! {
         delay.delay_ms(500_u16);
     }
 }
-
-fn display_ef(ef: &ExceptionFrame) {
-    struct Wrapper(ExceptionFrame);
-    impl defmt::Format for Wrapper {
-        fn format(&self, fmt: defmt::Formatter) {
-            defmt::write!(
-                fmt,
-                "ExceptionFrame(\n\tr0: {:08x}\n\tr1: {:08x}\n\tr2: {:08x}\n\tr3: {:08x}\n\tr12: {:08x}\n\tlr: {:08x}\n\tpc: {:08x}\n\txpsr: {:08x}\n)",
-                self.0.r0(),
-                self.0.r1(),
-                self.0.r2(),
-                self.0.r3(),
-                self.0.r12(),
-                self.0.lr(),
-                self.0.pc(),
-                self.0.xpsr()
-            );
-        }
-    }
-
-    error!("HardFault: Exception occured!");
-    error!("Exception occured at: {:08x}", ef.pc());
-    error!("XSPR: {:032b}", ef.xpsr());
-    error!("LR: {:08x}", ef.lr());
-
-    error!("HardFault: {:#?}", Wrapper(*ef))
-}
-
-#[allow(unreachable_code)]
-#[cortex_m_rt::exception(trampoline = true)]
-unsafe fn HardFault(ef: &ExceptionFrame) -> ! {
-    static mut EXCEPTION: Option<ExceptionFrame> = None;
-    unsafe { EXCEPTION = Some(*ef) };
-
-    display_ef(ef);
-    #[allow(clippy::empty_loop)]
-    loop {}
-}