GDB is a powerful text based debugger that is run from the terminal. We will use it extensively throughout this tutorial,
and start by examing the hello_x86 binary we just created. To begin, invoke the gdb debugger with:
gdb hello_x86
gdb hello_x86
pete@framework16:~/Documents/ASM/hello_world/x86$ gdb hello_x86
GNU gdb (Ubuntu 12.1-0ubuntu1~22.04) 12.1
Copyright (C) 2022 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later &l;thttp://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Type "show copying" and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<https://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from hello_x86...
(No debugging symbols found in hello_x86)
(gdb)
We are greated with the gdb prompt.
We wrote our assembly using the Intel syntax, so we will switch our disassembly output to that syntax with:
We wrote our assembly using the Intel syntax, so we will switch our disassembly output to that syntax with:
set disassembly-flavor intel
We want to view the disassembly code and the CPU registers while we are running our program, we can enable them with:
lay asm
lay reg
Your terminal window should now look similar this this:
|------------------------------------------------------------------------------------------------------------------------------------------|
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| [ Register Values Unavailable ] |
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|------------------------------------------------------------------------------------------------------------------------------------------|
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| [ No Assembly Available ] |
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|------------------------------------------------------------------------------------------------------------------------------------------|
exec No process In: L?? PC: ??
(gdb) lay reg
(gdb)
Note: If at any time the screen output appears corrupted, you can enter ctrl + l to redraw the screen.
You can use ctrl + x then o or p to switch between the assembly, register, and gdb command frames.
You can use ctrl + x then o or p to switch between the assembly, register, and gdb command frames.