From d87e6ea365500ca03c707e4440bff0cf04f7a4b1 Mon Sep 17 00:00:00 2001
From: rubenasplund <ruben.asplund@hotmail.com>
Date: Fri, 4 Dec 2020 18:47:32 +0100
Subject: [PATCH] Exercise F
---
examples/rtt_timing.rs | 39 ++++++++++++++++++++++++---------------
1 file changed, 24 insertions(+), 15 deletions(-)
diff --git a/examples/rtt_timing.rs b/examples/rtt_timing.rs
index 55ec247..878fed2 100644
--- a/examples/rtt_timing.rs
+++ b/examples/rtt_timing.rs
@@ -1,39 +1,44 @@
//! examples/rtt_timing.rs
-#![deny(unsafe_code)]
+//#![deny(unsafe_code)]
#![deny(warnings)]
#![no_main]
#![no_std]
use cortex_m::{asm, peripheral::DWT};
-use panic_rtt_target as _;
-use rtt_target::{rprintln, rtt_init_print};
+use panic_halt as _;
+//use panic_rtt_target as _;
+//use rtt_target::{rprintln, rtt_init_print};
use stm32f4;
#[rtic::app(device = stm32f4)]
const APP: () = {
#[init]
fn init(mut cx: init::Context) {
- rtt_init_print!();
- rprintln!("init");
+ //rtt_init_print!();
+ //rprintln!("init");
// Initialize (enable) the monotonic timer (CYCCNT)
cx.core.DCB.enable_trace();
cx.core.DWT.enable_cycle_counter();
- rprintln!("start timed_loop");
- let (start, end) = timed_loop();
- rprintln!(
- "start {}, end {}, diff {}",
- start,
- end,
- end.wrapping_sub(start)
- );
+ //rprintln!("start timed_loop");
+ //unsafe {
+ // cx.core.DWT.cyccnt.write(0);
+ //}
+
+ let (_start, _end) = timed_loop();
+ // rprintln!(
+ // "start {}, end {}, diff {}",
+ // start,
+ // end,
+ // end.wrapping_sub(start)
+ // );
}
#[idle]
fn idle(_cx: idle::Context) -> ! {
- rprintln!("idle");
+ // rprintln!("idle");
loop {
continue;
}
@@ -299,7 +304,7 @@ fn timed_loop() -> (u32, u32) {
// What is the initial value of the cycle counter
// (when hitting the `timed_loop` breakpoint)?
//
-// [Your answer here]
+// [0x00000006]
//
// ------------------------------------------------------------------------
// F) Finally some statics
@@ -340,6 +345,10 @@ fn timed_loop() -> (u32, u32) {
// > cargo size --example rtt_timing --release --features nightly
//
// [Your answer here]
+// Compiling app v0.1.0 (/home/ruben/git/rtic_f4xx_nucleo)
+// Finished release [optimized + debuginfo] target(s) in 0.44s
+// text data bss dec hex filename
+// 660 0 0 660 294 rtt_timing
//
// I was able to get down to:
// > cargo size --example rtt_timing --release --features nightly
--
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