bump the cortex-m-rt to v0.4.0

examples/allocator.rs

@@ -1,7 +1,6 @@
 //! How to use the heap and a dynamic memory allocator
 //!
-//! This example depends on the alloc-cortex-m crate so you'll have to add it
-//! to your Cargo.toml:
+//! This example depends on the alloc-cortex-m crate so you'll have to add it to your Cargo.toml:
 //!
 //! ``` text
 //! # or edit the Cargo.toml file manually
@@ -11,8 +10,8 @@
 //! ---
 
 #![feature(alloc)]
-#![feature(used)]
 #![feature(global_allocator)]
+#![feature(used)]
 #![no_std]
 
 // This is the allocator crate; you can use a different one
@@ -22,26 +21,27 @@ extern crate alloc;
 extern crate cortex_m;
 extern crate cortex_m_rt;
 extern crate cortex_m_semihosting;
+extern crate panic_abort; // panicking behavior
 
 use core::fmt::Write;
 
+use alloc_cortex_m::CortexMHeap;
 use cortex_m::asm;
 use cortex_m_semihosting::hio;
-use alloc_cortex_m::CortexMHeap;
 
 #[global_allocator]
 static ALLOCATOR: CortexMHeap = CortexMHeap::empty();
 
 extern "C" {
     static mut _sheap: u32;
-    static mut _eheap: u32;
 }
 
+const HEAP_SIZE: usize = 1024; // in bytes
+
 fn main() {
     // Initialize the allocator
     let start = unsafe { &mut _sheap as *mut u32 as usize };
-    let end = unsafe { &mut _eheap as *mut u32 as usize };
-    unsafe { ALLOCATOR.init(start, end - start) }
+    unsafe { ALLOCATOR.init(start, HEAP_SIZE) }
 
     // Growable array allocated on the heap
     let xs = vec![0, 1, 2];