fix itm::write_all

Author: japaric

CHANGELOG.md

@@ -7,7 +7,14 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
 
-## [v0.2.8] - 2017-05-30
+## [v0.2.9] - 2017-05-30
+
+### Fixed
+
+- A bug in `itm::write_all` where it would ignore the length of the buffer and
+  serialize contents that come after the buffer.
+
+## [v0.2.8] - 2017-05-30 - YANKED
 
 ### Added
 
@@ -279,7 +286,8 @@ fn main() {
 - Functions to get the vector table
 - Wrappers over miscellaneous instructions like `bkpt`
 
-[Unreleased]: https://github.com/japaric/cortex-m/compare/v0.2.8...HEAD
+[Unreleased]: https://github.com/japaric/cortex-m/compare/v0.2.9...HEAD
+[v0.2.9]: https://github.com/japaric/cortex-m/compare/v0.2.8...v0.2.9
 [v0.2.8]: https://github.com/japaric/cortex-m/compare/v0.2.7...v0.2.8
 [v0.2.7]: https://github.com/japaric/cortex-m/compare/v0.2.6...v0.2.7
 [v0.2.6]: https://github.com/japaric/cortex-m/compare/v0.2.5...v0.2.6

Cargo.toml

@@ -7,7 +7,7 @@ keywords = ["arm", "cortex-m", "register", "peripheral"]
 license = "MIT OR Apache-2.0"
 name = "cortex-m"
 repository = "https://github.com/japaric/cortex-m"
-version = "0.2.8"
+version = "0.2.9"
 
 [dependencies]
 aligned = "0.1.1"

src/itm.rs

@@ -31,6 +31,10 @@ pub fn write_all(port: &Stim, buffer: &[u8]) {
         let mut len = buffer.len();
         let mut ptr = buffer.as_ptr();
 
+        if len == 0 {
+            return;
+        }
+
         // 0x01 OR 0x03
         if ptr as usize % 2 == 1 {
             while !port.is_fifo_ready() {}
@@ -43,12 +47,23 @@ pub fn write_all(port: &Stim, buffer: &[u8]) {
 
         // 0x02
         if ptr as usize % 4 == 2 {
-            while !port.is_fifo_ready() {}
-            port.write_u16(ptr::read(ptr as *const u16));
-
-            // 0x04
-            ptr = ptr.offset(2);
-            len -= 2;
+            if len > 1 {
+                // at least 2 bytes
+                while !port.is_fifo_ready() {}
+                port.write_u16(ptr::read(ptr as *const u16));
+
+                // 0x04
+                ptr = ptr.offset(2);
+                len -= 2;
+            } else {
+                if len == 1 {
+                    // last byte
+                    while !port.is_fifo_ready() {}
+                    port.write_u8(*ptr);
+                }
+
+                return;
+            }
         }
 
         write_aligned(port, mem::transmute(slice::from_raw_parts(ptr, len)));