fix the allocator example

Cargo.toml

@@ -15,7 +15,6 @@ cortex-m-semihosting = "0.2.0"
 # Uncomment for the allocator example.
 #alloc-cortex-m = "0.3.2"
 
-
 [dependencies.cortex-m-rt]
 version = "0.3.12"
 # Comment for the panic example.

examples/allocator.rs

@@ -55,7 +55,7 @@ extern "C" {
 fn main() {
     // Initialize the allocator
     let start = unsafe { &mut _sheap as *mut u32 as usize };
-    let end = unsafe { &mut _sheap as *mut u32 as usize };
+    let end = unsafe { &mut _eheap as *mut u32 as usize };
     unsafe { ALLOCATOR.init(start, end - start) }
 
     // Growable array allocated on the heap

memory.x

@@ -18,3 +18,6 @@ MEMORY
 /* This is required only on microcontrollers that store some configuration right
    after the vector table */
 /* _stext = ORIGIN(FLASH) + 0x400; */
+
+/* Size of the heap (in bytes) */
+/* _heap_size = 1024; */