Breakpoints not hit.

Log in or register to post comments
Go To Last Post
5 posts / 0 new
Author
Message
BanksySan
BanksySan's picture
Level: New Member
Joined: Sun. Dec 19, 2021
Posts: 9 View posts
#1
Posted by BanksySan: Sun. Dec 19, 2021 - 04:33 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 1


I have a new project with some dummy code.

 

#include <avr/io.h>

int main(void) {
  const short foo = 10;

  while (1) {
    short bar;
    bar += foo;
  }
}

I have breakpoints on the const short foo = 10; line and bar += foo; line.  i have the debugger set to 

 

I have the Selected debugger/programmer set to Simulator.

 

If I run with debugging then the breakpoints are never hit.  They are hollowed out

 

 

If I pause the debugger then the next line is stuck before the first executable statement.

 

 

Trying to step over/into just causes the yellow marker to flash, but stay where it is.

 

This is my first attempt using Atmel Studio, I don't know what I might need to change in order to fix this.  I suspect that there's a process that it's waiting to attach to and not finding, but I don't know what that might be.

 

Any suggestions?

 

Thanks

 

Dave

This topic has a solution.

Tags:

Tools, Atmel Studio (AVR-related), # Atmel studio #ATmega328P #debugging #simulator, solved
Last Edited: Sun. Dec 19, 2021 - 04:58 PM
Top
Gold Markclawson
clawson's picture
Level: Moderator
Joined: Mon. Jul 18, 2005
Posts: 104964 View posts
Location: (using avr-gcc in) Finchingfield, Essex, England
This reply has been marked as the solution. 
Posted by clawson: Sun. Dec 19, 2021 - 04:39 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 1

You need to read my tutorial...

 

https://www.avrfreaks.net/forum/tutcoptimization-and-importance-volatile-gcc

 

Bottom line.. The optimizer will discard everything as the program doesn't actually do anything, it has no outputs. "volatile" basically says "this is an output that must be calculated / updated" 

Top
BanksySan
BanksySan's picture
Level: New Member
Joined: Sun. Dec 19, 2021
Posts: 9 View posts
Posted by BanksySan: Sun. Dec 19, 2021 - 04:58 PM (Reply to #2)
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Ah.  That makes perfect sense then.  I assumed (shouldn't have assumed) that as the config was debug mode that there wouldn't be any optimising things away.

Top
Gold Markclawson
clawson's picture
Level: Moderator
Joined: Mon. Jul 18, 2005
Posts: 104964 View posts
Location: (using avr-gcc in) Finchingfield, Essex, England
Posted by clawson: Sun. Dec 19, 2021 - 05:18 PM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

These days for "Debug" Studio 7 applies optimization level "-Og" but that still applies some optimization and will discard code that looks completely pointless. It's the same reason you can't just do a "for(int i=0; i < 10000; i++)" delay loop. Even at low levels of optimization the compiler will spot that it does not achieve anything so will discard the code.

 

Apart from "volatile" another good way to get things updated is to give them global scope as the compiler will assume the value may be used in another compilation unit. But if you did

foo = 13;
for (int i=0; i < 5: i++) foo += 3;

and foo were global all this would simply produce "foo = 28;" as that can be calculated at compile time. 

 

Because the AVR SFR registers like TCNT1, PORTB, DDRC, etc are all defined as "volatile" they are a good source and destination for inputs and outputs in "test code" as the compiler must write them when told and it cannot make any assumptions what value they return when read.

 

Bottom line : if you want to "test" some paradigm when using AVR just write real AVR code. 

 

If, on the other hand, you just want to see "computer science" in action you are far better doing that in PC code (Visual Studio say) when it builds "Debug" it really is the most sub-optimal, bloated/slow code but on a 3GHz octacore that doesn't actually matter! 

Top
BanksySan
BanksySan's picture
Level: New Member
Joined: Sun. Dec 19, 2021
Posts: 9 View posts
Posted by BanksySan: Sun. Dec 19, 2021 - 08:22 PM (Reply to #4)
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Writing to registers is a brilliant idea.  I didn't think of that 

Are the General Registers good for that?

Top