Here is the question:

A leaf function uses a number of S# registers to perform a particular operation. Which of the following statements are true about the use of S# $($save$)$ registers in relation to RISC$-$V$?($Select all that apply$)$

$1.$ Leaf functions can freely use S# registers without saving them, provided that they are not used by any subsequent function calls.

$2.$ Using S# registers in a leaf functions is most preferred for performance reasons.

$3.$ If a leaf function modifies an S# register, it must save the original value on the stack and restore it before returning, to maintain it on behalf of the calling convention.

$4.$ S# registers are also known as callee$-$saved registers, meaning the called function is responsible for saving and restoring their values if they are changed.

$5.$ Since a leaf function does not call other functions, it is not required to save the contents of S# registers before modifying them

$6.$ S# registers are typically used to store local variables or values that need to be preserved across function calls.

$7.$ S# registers $($e$.$g$.,$ s$0,$ s$1,$ etc.$)$ must be preserved across function calls, meaning that functions must save and restore their original values if it modifies them.

$8.$ Leaf functions are not allowed to modify S# registers because these registers are reserved for use by the calling function.