A hypothetical machine of Figure 3.4 as described in our lecture has two I/O instructions: 1101 (binary) = Load AC from I/O 0011 (binary) = Store AC to I/O In these cases, the 12bit address identifies a particular I/O device. Show the program execution for the following program (using the format of Figure 3.5 of the textbook as shown below) with clear explanation.

Load AC from device 15 (assume that the next balue retrieved from device 15 is 13)

Add contents of memory location 0x480. (assume that the content at location 0x480 is 24)

Store AC to device 48

Note: all numbers above should be treated as decimal number unless otherwise stated. Hexadecimal number has 0x as prefix, and the binary has a (binary) label after the number.

3 4 15 Opcode Address (a) Instruction format 0 15 Magnitude (b) Integer format Program counter (PC)-Address of instruction Instruction register (IR) = instruction being executed Accumulator (AC) = Temporary storage (c) Internal CPU registers 0001 = Load AC from memory 0010 = Store AC to memory 0101 Add to AC from memory (d) Partial list of opcodes Figure 3.4 Characteristics of a Hypothetical Machine