(1) Design and implement a part (the 12 bit register SP and POP machine instruction) of the Stack in the following schematic:
(1a)Make use of the units already in the schematic below, a part of CAPC, as much as possible, that is, design, build and attach a minimal number of black boxes by using basic gates, AND, OR, NOT, if absolutely necessary.
(1b) Try to make use of the pin 15 (originally allocated for NOP) of the Mach Decoder for the machine instruction "POP".
(1c) The instruction "POP" copies the 16 bit contents of the stack (in the memory pointed to by SP) to Greg, and then increments SP by 1, SP pointing the new top of the stack. Design the "POP" instruction by describing the required machine operations (Register-to-Register transfers) step by step (in subcycles). Wire the machine instruction "POP" in the schematic.
(1d) Could we add more machine instructions ? If your answer is affirmative, describe in detail how to (re)design and wire another machine instruction such as "PUSH".