Show Step By Step How a Machine Would Process This

Hypothetical Machine Instruction set

0001 Load AC from Memory

0010 Store AC to Memory

0011 Load AC from I/O

0100 - Add to AC from Memory

0101 Subtract AC from Memory

0110 Store AC to I/O

0111 Add to AC from Device

1000 Subtract Device from AC

1001 - Subtract AC from Device

1010 Halt Program

Begin Memory at location 500 and Program Counter at 500

Memory location 870 has 12 stored

Device 4 has 3 stored

Hypothetical machine should do the following code:

Load AC from memory 870

Subtract device 4 from AC

Store from AC to device 2

Add to AC from memory 870

Store AC to memory 871

Add to AC from device 4

Subtract device 2 from AC

Store from AC to memory 870

Add to AC from memory 871

Halt Program