Computer-Organization

Consider the following program fragment in the assembly language of a certain hypothetical processor. The processor has three general purpose registers R1, R2 and R3. The meanings of the instructions are shown by comments (starting with 😉 after the instructions.

X:  CMP R1, 0   ;  Compare R1 and 0, set flags appropriately in status register
    JZ  Z       ;  Jump if zero to target Z
    MOV R2, R1  ;  Copy contents of R1 to R2
    SHR R1      ;  Shift right R1 by 1 bit
    SHL R1      ;  Shift left R1 by 1 bit
    CMP R2, R1  ;  Compare R2 and R1 and set flag in status register
    JZ  Y       ;  Jump if zero to target Y
    INC R3      ;  Increment R3 by 1;
Y:  SHR R1      ;  Shift right R1 by 1 bit
    JMP X       ;  Jump to target X
Z:... 

(a) Initially R1, R2 and R3 contain the value 5, 0 and 0 respectively. What are the final values of R1 and R3 when control reaches Z?

(b) In general, if R1, R2 and R3 initially contain the values n, 0 and 0 respectively. What is the final value of R3 when control reaches Z?