I need to build a Logisim circuit in which I only have two inputs (two 8-bit immediates), an adder, and as many constants, inverters, and spitters as I need. I have 2 MUXs available to me and an Opcode that specifies the output. When the opcode is 00 or 10, I need A-1 and A-B as an output, respectively.
How do I do this with only an adder? That is, how do I subtract 1 from A and how do I subtract B from A with only an adder?
How do I do this with only an adder? That is, how do I subtract 1 from A and how do I subtract B from A with only an adder?