What's the difference between nexti and stepi in gdb?

stepi is more detailed than nexti. if you call sum() from main() function then doing stepi reaches you inside the sum() function, but nexti doesn't.

Below is the screenshot when you call stepi when you were at call of sum() instruction (i.e., => 0x08048403 <+40>: call 0x8048419 <sum>). The stepi instuction routes you inside the sum().

If you do nexti when you were at call of sum() instruction (i.e., => 0x08048403 <+40>: call 0x8048419 <sum>) then it uses the returned value from sum method and goes to the next instruction of main method, screenshot as below.

Conclusion: Use stepi if you want to see every machine instructions that happened in your processor. Use nexti if you wanna see only the machine instructions executed at the main().

The difference is how call is treated:

• stepi dives into call
• nexti runs call but doesn't walk you through its code