From b0f554ff207cefd5dd73b243b3fb9699fcce72b9 Mon Sep 17 00:00:00 2001
From: Grumme2 <agh@live.se>
Date: Wed, 15 Apr 2020 15:15:49 +0200
Subject: [PATCH] bare1_4
---
examples/bare1.rs | 21 +++++++++++++++++----
1 file changed, 17 insertions(+), 4 deletions(-)
diff --git a/examples/bare1.rs b/examples/bare1.rs
index 4c548ce..18c75d5 100644
--- a/examples/bare1.rs
+++ b/examples/bare1.rs
@@ -24,9 +24,9 @@ fn main() -> ! {
cortex_m::asm::bkpt();
// prevent optimization by read-volatile (unsafe)
- unsafe {
- core::ptr::read_volatile(&x);
- }
+ // unsafe {
+ // core::ptr::read_volatile(&x);
+ // }
}
}
@@ -205,15 +205,28 @@ fn main() -> ! {
// > disassemble
//
// ** your answer here **
+//
+// Dump of assembler code for function bare1::__cortex_m_rt_main:
+// 0x0800040a <+0>: bkpt 0x0000
+// => 0x0800040c <+2>: bkpt 0x0000
+// 0x0800040e <+4>: b.n 0x800040a <bare1::__cortex_m_rt_main>
+// End of assembler dump
//
// How many instructions are in between the two `bkpt` instructions.
//
// ** your answer here **
-//
+// 0
+//
// Where is the local variable stored?
// What happened, and why is Rust + LLVM allowed to do that?
//
// ** your answer here **
+//
+// 0x0800040e <+4>: b.n 0x800040a <bare1::__cortex_m_rt_main>
+//
+// In release mode the program is the most optimized
+// which means that the compiler can remove instructions that arent necessary
+//
//
// commit your answers (bare1_4)
//
--
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