For the instructions below, assume the initial conditions shown for r3-r5 and the flags. Show the value of any registers that are changed. If the instruction affects flags, show the value for all affected flags and explain the reason.

The machine instruction cycle is: A Fetch - process - decode. B Fetch execute - process. C Fetch - decode – execute. D Fetch- execuie- decode.

7. For both of the instructions shown below, the initial conditions are shown. The result (which the instruction stores in r1) is also shown. For each instruction, answer these questions: • What is the state of the flags (NZCV) after the instruction executes • If the operands were signed, are the results valid? Why or why not? • If the operands were unsigned, are the results valid? Why or why not? a) initial conditions: r0 = 0xAAAA_AAAA rl=0x5555_5555 ADDS rl,rl,ro Result: r1=0xFFFF_FFFF b) initial conditions: r0=0x7FFF_FFFD r1 = 0x0000_000F ADDS rl,ro,r1 Result: r1=0x8000_000C

Describe the concept of flags or condition codes in the context of ALU instructions. Why are they important?