subroutine call

Question

I know function call is like subroutine call. But why it is differentiate from function call?

 

and if a processor calls a subroutine is any interrupt is possible?means what is the relationship of subroutine call and interrupt?

Answer 1

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 relatively independent of the remaining code.

The interrupt service routine is just like a subroutine. The difference is that when you call a
subroutine, you call it when you decide, and you understand completely what will be changed by the subroutine,

Interrupt Service Routines (ISRs) are to handle hardware interrupts.