1. 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. Care Should be taken while returning a Subroutine as Subroutine can be called from a different place from the memory.
The content of the PC must be Saved by the call Subroutine Instruction to make a correct return to the calling program.
Subroutine linkage method is a way in which computer call and return the Subroutine. The simplest way of Subroutine linkage is saving the return address in a specific location, such as register which can be called as link register call Subroutine.
2. Subroutine Nesting –
Subroutine nesting is a common Programming practice In which one Subroutine call another Subroutine.
From the above figure, assume that when Subroutine 1 calls Subroutine 2 the return address of Subroutine 2 should be saved somewhere. So if link register stores return address of Subroutine 1 this will be (destroyed/overwritten) by return address of Subroutine 2. As the last Subroutine called is the first one to be returned ( Last in first out format). So stack data structure is the most efficient way to store the return addresses of the Subroutines.
3. Stack memory –
Stack is a basic data structure which can be implemented anywhere in the memory. It can be used to store variables which may be required afterwards in the program Execution. In a stack, the first data put will be last to get out of a stack. So the last data added will be the First one to come out of the stack (last in first out).
So from the diagram above first A is added then B & C. While removing first C is Removed then B & A.
- Introduction to memory and memory units
- Difference between Byte Addressable Memory and Word Addressable Memory
- Infix to Postfix using different Precedence Values for In-Stack and Out-Stack
- Stack Permutations (Check if an array is stack permutation of other)
- Find maximum in stack in O(1) without using additional stack
- Stack | Set 3 (Reverse a string using stack)
- Sort a stack using a temporary stack
- Secondary Memory
- 2D and 2.5D Memory organization
- Types of computer memory (RAM and ROM)
- Memory mapped I/O and Isolated I/O
- Computer Organisation | One bit memory cell
- How the negative numbers are stored in memory?
- Different Types of RAM (Random Access Memory )
- Memory Segmentation in 8086 Microprocessor
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