Subroutine
From HomoExcelsior
1. A set of programming instructions designed to perform a specific,
well
defined task. 2. A routine, function, procedure, method.
One calls a routine to transfer
control of the code execution to a new point in memory temporarily.
The new code path is expected to return control to the place
in memory immediately following the instruction which caused
the call to the subroutine initially.
Most CPUs have several
machine code instructions for calling subroutines, such as
jump and return. The jump instruction may store the
current position in memory on a stack
so that the "return from jump" can return to the code section
which made the "subroutine call" (jump).
Some computer programming languages distinguish between
subroutine which return values (often called functions), and
those which do not (often called procedures).
