What does RET instruction do in assembly?

Description. The ret instruction transfers control to the return address located on the stack. This address is usually placed on the stack by a call instruction. Issue the ret instruction within the called procedure to resume execution flow at the instruction following the call .

What is RSP and RBP?

rbp is the base pointer, which points to the base of the current stack frame, and rsp is the stack pointer, which points to the top of the current stack frame.

What is RSP used for?

The rsp and the rbp are used to keep track of the stack frame. With rbp referring to the base pointer (the previous top of the stack) and rsp pointing (ideally) always to the current top of the stack. mov rbp rsp // This puts the base pointer at the current head of the stack pointing at the, just pushed, old rbp.

What is RSI Assembly?

rsi – register source index (source for data copies) rdi – register destination index (destination for data copies)

What is RET equivalent to in assembly?

ret is basically how you write pop eip (or IP / RIP) in x86, so popping into an architectural register and using a register-indirect jump is architecturally equivalent.

What does leave and RET do in assembly?

Description. The leave instruction reverses the actions of an enter instruction. leave copies the frame pointer to the stack point and releases the stack space formerly used by a procedure for its local variables. A subsequent ret nn instruction removes any arguments pushed onto the stack of the exiting procedure.

Is RSP a general purpose register?

According to Intel in x64 the following registers are called general purpose registers (RAX, RBX, RCX, RDX, RBP, RSI, RDI, RSP and R8-R15) https://software.intel.com/en-us/articles/introduction-to-x64-assembly.

What is sub RSP?

This convention is used by all functions, including other functions you call. It’s a very common way for you or the compiler to allocate a few bytes of temporary space in a function, like for local variables. So to claim 8 bytes of stack space, you just “sub rsp,8”.

Where does RSP point to?

The stack grows down in memory; %rsp points to the lowest occupied stack location (not to the next one to use). Register %rbp is sometimes used as a frame pointer, i.e., the base of the current stack frame. The enter and leave instructions make implicit reference to it.

What is the RSI register for?

Architectures define a calling convention which dictates where parameters to a function and its return value are stored. In Objective-C, the RDI register is the reference of the calling NSObject , RSI is the Selector, RDX is the first parameter and so on.

What is the use of RSI and RDI registers?

Registers

Register	Purpose	Saved across calls
%rsi	used to pass 2nd argument to functions	No
%rdi	used to pass 1st argument to functions	No
%r8	used to pass 5th argument to functions	No
%r9	used to pass 6th argument to functions	No

What does Ret mean in programming?

return from
ret, return from subroutine instruction in the x86 assembly language.