What does ebp and esp in a disassembly code mean?

Question

Below posted is my code. Help me out in understanding what the below code means:

   push    ebp
   mov     ebp, esp
   sub     esp, 230h

Serology

Related: #20695703 – Martinamartindale

Possible duplicate of why to use ebp in function prologue/epilogue? – Jejunum

Related: #21718897 – Kaufman

Answer 1

It is a function prologue.

Pushes the old base pointer onto the stack, so it can be restored later:

   push    ebp

Assigns the value of stack pointer into base pointer, then a new stack frame will be created on top of the old stack frame:

   mov     ebp, esp

Moves the stack pointer further by decreasing or increasing its value (depending on whether the stack grows down or up):

   sub     esp, 230h

Here, the230h immediate value is the number of bytes reserved on the stack for local use in the function.

In a similar way, the function epilogue reverses the actions of the prologue and returns control to the calling function.

Check this related SO question: Function Prologue and Epilogue in C

Dyspnea

Some compilers offer the option of not using frame pointers, which frees up ebp to be used as a generic register (it would still need to be saved). – Spohr