GDB Debug Assembler Stack Process analysis

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Use gcc -g example.c -o example -m32 instructions to generate a 32-bit assembly on a 64-bit machine gdb example , and then use the instructions to enter the GDB debugger.

After entering, set a breakpoint at the main function, run again, use disassemble the instructions to get the assembly code, and use i(info) r(registers) the instructions to see the values of each register:

The stack base of the main function is 0xffffcf98

x(examine)view values in memory address with directives %esp : 0, %ebp : 0

The call instruction adds the address of the next instruction to the stack, at which point the value of the %esp %ebp stack is:

Put the base address of the previous function into the stack, starting with the current %esp base:

Prepare for the transfer of the parameters first:

The calculation of the arguments is %eax performed in:

Assembly code for the F function:

Actual argument into the stack:

The call command will put the address of the next instruction into the stack:

Calculate Short+int:

pop %ebpThe instruction pushes the stack top to %ebp medium and %esp adds 4 bytes:

The RET instruction will reload the stack top to %eip :

Because the function f has been modified %esp , it is restored with the leave command. The leave instruction will first %esp go to it and %ebp then reload the top of the stack to %ebp :

Main function assembly code:

GDB Debug Assembler Stack Process analysis