971 simple adder and subtractor :: Quicker, easier and cheaper to make your own chip!

971 : simple adder and subtractor

Author: Alexander Brandstetter

Description: full adder and full subtactor with 2 4bit registers

Clock: 0 Hz

2 4 bit registers fed into a full adder and a full subtractor, the output is chosen via mux

in input 0-3 give the data in binary, swich registers with input 4, choose the output with input 7

none required, however to see the output leds are quite nice, to choose the input switches are also a qol feature

#	Input	Output
0	data in 1	data out 1
1	data in 2	data out 2
2	data in 3	data out 3
3	data in 4	data out 4
4	select register to write 1 or 2, logic 1 means write register 1, logic 0 means write register 2	data out 5, for addition
5
6
7	choose between add and subtract, add is logic 1, subtract is logic 0	overflow for subract, meaning below 0

Input

Output

Bidirectional

data in 1

data out 1

data in 2

data out 2

data in 3

data out 3

data in 4

data out 4

select register to write 1 or 2, logic 1 means write register 1, logic 0 means write register 2

data out 5, for addition

choose between add and subtract, add is logic 1, subtract is logic 0

overflow for subract, meaning below 0

Chip location

971 simple adder and subtractor