From 07b232694b5f911821460599d1d0659eacffd3f0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Edvin=20=C3=85kerfeldt?= <Edvin Åkerfeldt>
Date: Fri, 4 Dec 2020 11:50:20 +0100
Subject: [PATCH] timing_task, all questions done
---
.cargo/config | 4 ++--
examples/timing_task.rs | 23 +++++++++++++++++++++++
2 files changed, 25 insertions(+), 2 deletions(-)
diff --git a/.cargo/config b/.cargo/config
index 5d4b78a..ce50de7 100644
--- a/.cargo/config
+++ b/.cargo/config
@@ -5,10 +5,10 @@
[target.'cfg(all(target_arch = "arm", target_os = "none"))']
# uncomment ONE of these three option to make `cargo run` start a GDB session
# which option to pick depends on your system
-# runner = "arm-none-eabi-gdb -q -x openocd.gdb"
+runner = "arm-none-eabi-gdb -q -x openocd.gdb"
# runner = "gdb-multiarch -q -x openocd.gdb"
# runner = "gdb -q -x openocd.gdb"
-runner = "probe-run --chip STM32F411RETx"
+# runner = "probe-run --chip STM32F411RETx"
rustflags = [
# This is needed if your flash or ram addresses are not aligned to 0x10000 in memory.x
diff --git a/examples/timing_task.rs b/examples/timing_task.rs
index e972a8a..947ba89 100644
--- a/examples/timing_task.rs
+++ b/examples/timing_task.rs
@@ -82,10 +82,23 @@ const APP: () = {
// (gdb) x 0xe0001004
//
// [Your answer here]
+/*
+(gdb) x/d 0xe0001004
+0xe0001004: 11
+*/
//
// (gdb) disassemble
//
// [Your answer here]
+/*
+(gdb) disassemble
+Dump of assembler code for function timing_task::APP::EXTI0:
+=> 0x08000232 <+0>: bkpt 0x0000
+ 0x08000234 <+2>: movs r0, #0
+ 0x08000236 <+4>: msr BASEPRI, r0
+ 0x0800023a <+8>: bx lr
+End of assembler dump.
+*/
//
// You should see that we hit the breakpoint in `exti0`, and
// that the code complies to the objdump EXTI disassembly.
@@ -96,10 +109,16 @@ const APP: () = {
// What was the software latency observed to enter the task?
//
// [Your answer here]
+/*
+None, only hardware latenvy to enter the task.
+*/
//
// Does RTIC infer any overhead for launching the task?
//
// [Your answer here]
+/*
+No, the MCU jumps strait to the first useful intstruction in the exception.
+*/
//
// Now we can continue to measure the round trip time.
//
@@ -110,6 +129,10 @@ const APP: () = {
// (gdb) x 0xe0001004
//
// [Your answer here]
+/*
+(gdb) x/d 0xe0001004
+0xe0001004: 23
+*/
//
// Looking at the EXTI0 (exti0) code, we see two additional
// instructions used to restore the BASEPRI register.
--
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