How do I read the Symboltable generated by objdump --disassemble, i.e. what does each column mean?

Asked Nov 26 '20 at 13:34

Active Nov 26 '20 at 14:14

Viewed 66 times

This is an excerpt of what I get but I don't understand it. I recognise the instructions but for example what is in the second column?

Disassembly of section .text._ZNSt10_Head_baseILm0EOeLb0EE7_M_headERS1_:
_ZNSt10_Head_baseILm0EOeLb0EE7_M_headERS1_:
       0:   55               pushq   %rbp
       1:   48 89 e5         movq    %rsp, %rbp
       4:   48 89 7d f8      movq    %rdi, -8(%rbp)
       8:   48 8b 45 f8      movq    -8(%rbp), %rax
       c:   48 8b 00         movq    (%rax), %rax
       f:   5d               popq    %rbp
      10:   c3               retq

edited Nov 26 '20 at 14:14

asked Nov 26 '20 at 13:34

Michel Ruge

which column, the `48 89 e5`? Those are the actual bytes of the instruction (in hex) – user253751 Nov 26 '20 at 13:37
ohh okay, so what happens when the last column is empty? – Michel Ruge Nov 26 '20 at 14:08
I don't get which column you're asking about. Note that in your question, the columns aren't lined up properly – user253751 Nov 26 '20 at 14:12
I think I fixed it (sorry, how it was before was how my computer formatted it) and I think I understand now as well. So the first column is the bytes of the instruction in hex, the second column is the instruction and the third column is where what the instruction does is saved? – Michel Ruge Nov 26 '20 at 14:16
The third and fourth columns are the instruction – user253751 Nov 26 '20 at 14:35
Okay and if the fourth column is empty? for example in the last row – Michel Ruge Nov 26 '20 at 14:40
The third and fourth columns are the instruction. `pushq %rbp` is an instruction, so is `retq` – user253751 Nov 26 '20 at 14:42
I think what you are looking for might be already answered here: https://stackoverflow.com/a/48552426/2731508 – ashu Nov 26 '20 at 17:20

How do I read the Symboltable generated by objdump --disassemble, i.e. what does each column mean?

0 Answers0