Whenever we get input from user, using assembly language, the ASCII code of digit/letter stores in register 'AL'. In the same way I want to know if I press like 'Ctrl+C' , 'Ctrl+V' or 'Ctrl+X' etc what actions are performed by the system i.e.,
Mainly my focus is to know the internal operations performed by the hardware on above instructions.
In very broad terms, this functionality is defined by the keyboard routines in the BIOS. This document, although MS-DOS focused, provides a fairly good explanation of the low level BIOS keyboard routines. In the standard PC BIOS as described here, you would generally need to interpret the value of the AH register which contains the scan code of the keystroke. For example, on the standard US PC-AT keyboard, the key down scan code for left Ctrl is 0x1D.