rtt_timing done

examples/rtt_timing.rs

@@ -212,6 +212,10 @@ fn timed_loop() -> (u32, u32) {
 // https://developer.arm.com/documentation/ddi0439/b/Data-Watchpoint-and-Trace-Unit/DWT-Programmers-Model
 //
 // [Your answer here]
+// With movw and movt the value 0xe0001004 is loaded to register 1.
+// The address to DWT::get_cycle_count() is the value 0xe0001004.
+// Then with the ldr, the value of the DWT::get_cycle_count() is loaded into register r0.
+// 
 //
 // Now check your answer by dumping the registers
 // (gdb) info registers