Update skip-data-init example

Author: KushalMeghani1644

cortex-m-rt/examples/skip-data-init.rs

@@ -1,5 +1,5 @@
 //! Example demonstrating the skip-data-init feature
-//! 
+//!
 //! This feature is useful when using bootloaders (like RP2040's boot2) that:
 //! 1. Copy all data from Flash to RAM
 //! 2. Unmap the Flash from memory space
@@ -20,18 +20,26 @@
 #![no_main]
 #![no_std]
 
-use panic_halt as _;
-
 use cortex_m_rt::entry;
+use cortex_m_semihosting::hprintln;
+use panic_halt as _;
 
 static mut COUNTER: u32 = 42;
 
 #[entry]
 fn main() -> ! {
-    unsafe {
+    let (prev, new) = unsafe {
         COUNTER += 1;
+        (COUNTER - 1, COUNTER)
+    };
+
+    hprintln!("Previous counter value: {}", prev);
+    hprintln!("New counter value: {}", new);
+
+    if prev != 42 || new != 43 {
+        panic!("Unexpected COUNTER value! Data section may not be initialized.");
     }
-    
+
     loop {
         cortex_m::asm::nop();
     }