This is a simulator of the CARDIAC Cardboard Computer. Three digit instructions can be entered into the memory slots, or loaded by input card. This simulator will run the CARDIAC machine codes and perform the Arithmetic Logic based on the following instruction set:

0 INP read a card into memory,
1 CLA clear accumulator and add from memory (load),
2 ADD add from memory to accumulator,
3 TAC test accumulator and jump if negative,
4 SFT shift accumulator,
5 OUT write memory location to output card,
6 STO store accumulator to memory,
7 SUB subtract memory from accumulator,
8 JMP jump and save PC,
9 HRS halt and reset.

An example opcode is "001," which is the instruction "0" and the memory offset "01." The simulator will process this opcode by inputting a value from a preloaded card into the memory location 01.