Question

What two actions does the RETI instruction perf orm? Why must these two actions be done in a single instruction, as opposed to allowing the programmer to use multiple instructions?

Answer 1

Answer:

In assembly language, two instructions control the use of the assembly language procedure.

• CALL
• RET

CALL pushed the control to the return address onto the stack and transferred the control.

RET instruction returns the address that placed on the stack by a call instruction.

Explanation:

Action RET instruction

• The RET instruction pops the address and returns off the stack, which is pointed by the stack pointer.
• The stack is LIFO in memory at a particular location, and the pointer points offset from the stack location.

RET instruction does its job by consulting the register and memory state at the point when it is executed.

In RET instruction, only register and memory state is executed. Call instruction must save that address that figure out in a register and memory location.