Question

I am new to debugging an assembly code under gdb.Therefore, I have some question;

• How can I run my assembly code (At virtual place ) without actually running it ?

• If it needs a value, how can I insert a value to see how it works for each case in switch statement?

  ex: I couldnot give example on assembly so I give it in c.

      scanf ( "%d",&y);
      while ( y ) {
           ...
           scanf( "%d", &x);
           switch ( x ) {
  
           case 1: ...
           case 2: ...
           case 3: ...
           }
  
       }
  

• If I need, how can I know what value is stored in a register ?

• How can I print out all display to my .txt file ? In other words, assume I have started my program and it runs with no break point and then I want print this display to .txt file. So, I can work on paper. As You know, paper is more powerful than computer 🙂

I know some of you will say “go and read gdb tutorial or man page”.But, I could not find any good tutorials, with example to explain how a command works. My brain only works when my eyes see example 🙂

Platform is Linux
Tool is terminal/console

EDIT : Please give me a good website including good documentation, of course If you know

Give me documentation of “how to [catch] fish”, “not how to eat fish”

Answer 1

How can I run my assembly code without actually running it ?

Umm, err, what?!

If it needs a value, how can I insert a value to see how it works for each case in switch statement?

set whatever = some expression

Remember that registers have a $ sigil (e.g: $eax).

If I need, how can I know what value is stored in a register ?

For all registers:

info reg

For a specific register

info reg $eax

or

p $eax

or

p/x $eax

etc…

How can I print out all display to my .txt file ? In other words, assume I have started my program and it runs with no break point and then I want print this display to .txt file. So, I can work on paper. As You know, paper is more powerful than computer 🙂

set logging file foobar.out
set logging on