Quick Answer: What Is Subroutine Call And Return?

How do you read a call stack?

Call stack is set of lines, which is usually read from top to bottom – meaning moving from current locations to callers.

The bottom line was executed first.

The top line is executed last and it is the current routine..

Why return statement is used in a subroutine call?

In computer programming, a return statement causes execution to leave the current subroutine and resume at the point in the code immediately after the instruction which called the subroutine, known as its return address.

How stack is used in subroutine call?

Stack – Calling a subroutine The executing program maintains a stack to help control the flow of instructions. A program is often divided up into a main loop that calls a number of ‘subroutines’. Each subroutine has a specific task.

What is subroutine with example?

A routine or subroutine, also referred to as a function, procedure, and subprogram, is code called and executed anywhere in a program. For example, a routine may be used to save a file or display the time.

What is difference between function and subroutine?

Functions and subroutines operate similarly but have one key difference. A function is used when a value is returned to the calling routine, while a subroutine is used when a desired task is needed, but no value is returned.

What instruction is used to call a subroutine?

A set of Instructions which are used repeatedly in a program can be referred to as Subroutine. Only one copy of this Instruction is stored in the memory. When a Subroutine is required it can be called many times during the Execution of a Particular program. A call Subroutine Instruction calls the Subroutine.

What is stack and subroutine?

The stack is a LIFO (last in, first out) data structure implemented in the RAM area and is used to store addresses and data when the microprocessor branches to a subroutine. Then the return address used to get pushed on this stack. Also to swap values of two registers and register pairs we use the stack as well.

How is a subroutine used?

In computer programming, a subroutine is a sequence of program instructions that performs a specific task, packaged as a unit. This unit can then be used in programs wherever that particular task should be performed.

WHAT IS function and procedure?

A procedure performs a task, whereas a function produces information. Functions differ from procedures in that functions return values, unlike procedures which do not. However, parameters can be passed to both procedures and functions. In a program for drawing shapes, the program could ask the user what shape to draw.

What is a subroutine call?

In computer: Central processing unit. A related instruction is the subroutine call, which transfers execution to a subprogram and then, after the subprogram finishes, returns to the main program where it left off.

What is the difference between interrupt and subroutine call?

Simply, a subroutine is code you write and call as required, an interrupt is system bound and cannot be called by the user but occurs when something happens (sources are hardware, software and CPU) that requires immediate attention.

What are the two types of subroutines?

There are two types of subroutine:procedures.functions.