initial commit with my changes

examples/allocator.rs

@@ -0,0 +1,56 @@
+//! 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:
+//!
+//! ``` text
+//! # or edit the Cargo.toml file manually
+//! $ cargo add alloc-cortex-m
+//! ```
+//!
+//! ---
+
+#![feature(alloc_error_handler)]
+#![no_main]
+#![no_std]
+
+extern crate alloc;
+use panic_halt as _;
+
+use self::alloc::vec;
+use core::alloc::Layout;
+
+use alloc_cortex_m::CortexMHeap;
+use cortex_m::asm;
+use cortex_m_rt::entry;
+use cortex_m_semihosting::{hprintln, debug};
+
+// this is the allocator the application will use
+#[global_allocator]
+static ALLOCATOR: CortexMHeap = CortexMHeap::empty();
+
+const HEAP_SIZE: usize = 1024; // in bytes
+
+#[entry]
+fn main() -> ! {
+    // Initialize the allocator BEFORE you use it
+    unsafe { ALLOCATOR.init(cortex_m_rt::heap_start() as usize, HEAP_SIZE) }
+
+    // Growable array allocated on the heap
+    let xs = vec![0, 1, 2];
+
+    hprintln!("{:?}", xs).unwrap();
+
+    // exit QEMU
+    // NOTE do not run this on hardware; it can corrupt OpenOCD state
+    debug::exit(debug::EXIT_SUCCESS);
+
+    loop {}
+}
+
+// define what happens in an Out Of Memory (OOM) condition
+#[alloc_error_handler]
+fn alloc_error(_layout: Layout) -> ! {
+    asm::bkpt();
+
+    loop {}
+}