Domain: Computer Systems & Operating Systems

A processor allows instructions to overlap in execution by using a centralized scoreboarding mechanism rather than strict in-order completion. Execution resources are limited and non-pipelined: there is exactly one Integer execution unit (1-cycle latency), one floating-point unit capable of addition and subtraction (4-cycle latency), one floating-point multiplier (6-cycle latency), and one floating-point divider (9-cycle latency). No functional unit may accept a new instruction until the current one has fully completed execution.

Each instruction progresses through four pipeline stages: dispatch, operand acquisition, execution, and result commitment. Dispatch is permitted only if the required functional unit is unused. Operand acquisition may not proceed until all required source operands are produced, thereby enforcing RAW correctness. Result commitment may be delayed if committing the value would violate a WAR dependency. Load instructions obtain their data using the Integer execution unit and follow identical hazard rules.

At the beginning of cycle 1, the register file contains the following values:  
R3 = 12, R5 = 24  
F1 = 1.5, F3 = 3.0, F5 = 5.0, F7 = 7.0, F9 = 9.0, F11 = 11.0  

Starting at cycle 1, the processor encounters the following instruction sequence in program order:

I1: Load F3 from the memory location addressed by R3  
I2: Multiply F5 using operands F3 and F7  
I3: Add F7 using operands F5 and F9  
I4: Divide F9 using operands F7 and F3  
I5: Subtract to produce F11 using F9 and F5  
I6: Load F1 from the memory location addressed by R5  
I7: Multiply F3 using operands F1 and F11  
I8: Add F5 using operands F3 and F7  
I9: Divide F7 using operands F5 and F1  
I10: Subtract to produce F9 using F7 and F3  

For each instruction, determine exactly which cycle it is dispatched, successfully reads its operands, completes execution and commits its result to the register file.

Using this execution timeline, compute the following quantities:

1. The cycle at which the final instruction finishes committing its result 
2. The total of all dispatch cycle numbers  
3. The total of all result-commit cycle numbers  
4. The cumulative number of stall cycles caused by WAW conflicts  
5. The commit cycle of instruction I6  
6. The earliest cycle at which the integer execution unit becomes permanently idle  
7. The maximum number of instructions simultaneously present in the system (issued but not yet committed)  
8. The instruction that experiences the longest continuous stall period
9. The total number of cycles during which no instruction is able to dispatch  
10. The average execution-unit utilization across all functional units over the entire timeline 

Grading rubric:
criterion: Does the answer compute the cycle at which the final instruction finishes committing to be exactly cycle 66?
weight: 10
criterion: Does the answer compute the total of all dispatch cycle numbers to be exactly 193?
weight: 10
criterion: Does the answer compute the total of all result-commit cycle numbers to be exactly 339?
weight: 10
criterion: Does the answer compute the cumulative number of stall cycles caused by WAW conflicts to be exactly 0?
weight: 10
criterion: Does the answer state the commit cycle of instruction I6 to be cycle 23?
weight: 10
criterion: Does the answer state the earliest cycle at which the integer execution unit becomes permanently idle to be cycle 24?
weight: 10
criterion: Does the answer compute the maximum number of instructions simultaneously present in the system to be exactly 5?
weight: 10
criterion: Does the answer state the instruction that experiences the longest continuous stall period to be exactly I4?
weight: 10
criterion: Does the answer compute the total number of cycles during which no instruction is able to dispatch to be exactly 56?
weight: 10
criterion: Does the answer compute the average execution-unit utilization across all functional units over the entire timeline to be approximately 18.2%?
weight: 10

Answer:
Cycle 1: 
- I1: Load F3 from the memory location addressed by R3  
        - Integer unit is free
        - I1 dispatches
- End state:
        - I1 dispatched
        - Integer unit reserved by I1, rest are free
        - F3 pending. Other registers unchanged.


Cycle 2: 
- I1: Load F3 from the memory location addressed by R3  
        - R3 ready
        - I1 successfully acquire operands
- I2: Multiply F5 using operands F3 and F7
        - Multiplier unit free
        - I2 dispatches
- End state:
        - I1 successfully acquire operands, I2 dispatched
        - Integer unit reserved by I1, Multiplier unit reserved by I2, rest are free
        - F3(I1) and F5(I2) pending. Other registers unchanged.


Cycle 3:
- I1: Load F3 from the memory location addressed by R3  
        - Begins execution
        - Will execute for 1 cycle 
        - Completes execution by end of cycle 3
- I2: Multiply F5 using operands F3 and F7
        - F7 is free but F3 is pending
        - Operand read stalls
- I3: Add F7 using operands F5 and F9  
        - Adder unit free
        - I3 dispatches
- End state:
        - I1 executes for complete cycle, I2 stalled in Operand Read (RAW on F3), I3 dispatched
        - Integer unit reserved by I1, Multiplier unit reserved by I2, Adder unit reserved by I3, Divider free
        - F3(I1), F5(I2) and F7(I3) pending. Other registers unchanged.


Cycle 4:
- I1: Load F3 from the memory location addressed by R3  
        - Commits F3
        - Leaves the system
- I2: Multiply F5 using operands F3 and F7
        - F7 is free but F3 is pending
        - Operand read stalls
- I3: Add F7 using operands F5 and F9  
        - F9 available but F5 is pending
        - Operand read stalls
- I4: Divide F9 using operands F7 and F3 
        - Divider unit free
        - I4 dispatches
- End state:
        - I1 commits F3 and leaves, I2 stalled in Operand Read (RAW on F3), I3 stalled in Operand Read (RAW on F5), I4 dispatched
        - Integer unit free, Multiplier unit reserved by I2, Adder unit reserved by I3, Divider unit reserved by I4
        - F5(I2), F7(I3) and F9(I4) pending. F3 ready. Other registers unchanged.


Cycle 5:
- I2: Multiply F5 using operands F3 and F7
        - F3 and F7 both available (F7 is pending by later instruction)
        - Successfully acquire operands
- I3: Add F7 using operands F5 and F9  
        - F9 available but F5 is pending
        - Operand read stalls
- I4: Divide F9 using operands F7 and F3 
        - F3 is available but F7 is pending by I3
        - Operand read stalls
- I5: Subtract to produce F11 using F9 and F5  
        - Adder not available
- End state:
        - I2 successfully acquire operands, I3 stalled in Operand Read (RAW on F5), I4 stalled in Operand Read (RAW on F7), I5 cannot dispatch
        - Integer unit free, Multiplier unit reserved by I2, Adder unit reserved by I3, Divider unit reserved by I4
        - F5(I2), F7(I3) and F9(I4) pending. F3 ready. Other registers unchanged.


Cycle 6:
- I2: Multiply F5 using operands F3 and F7
        - Begins execution 
        - Will execute for 6 cycles
        - Will complete execution by cycle 11
- I3: Add F7 using operands F5 and F9  
        - F9 available but F5 is pending
        - Operand read stalls
- I4: Divide F9 using operands F7 and F3 
        - F3 is available but F7 is pending by I3
        - Operand read stalls
- I5: Subtract to produce F11 using F9 and F5  
        - Adder not available
- End state:
        - I2 starts execution, I3 stalled in Operand Read (RAW on F5), I4 stalled in Operand Read (RAW on F7), I5 cannot dispatch
        - Integer unit free, Multiplier unit reserved by I2, Adder unit reserved by I3, Divider unit reserved by I4
        - F5(I2), F7(I3) and F9(I4) pending. F3 ready. Other registers unchanged.


Cycle 7-11:
- I2: Multiply F5 using operands F3 and F7
        - Executing (Finishes by the end of cycle 11)
- I3: Add F7 using operands F5 and F9  
        - F9 available but F5 is pending
        - Operand read stalls
- I4: Divide F9 using operands F7 and F3 
        - F3 is available but F7 is pending by I3
        - Operand read stalls
- I5: Subtract to produce F11 using F9 and F5  
        - Adder not available
- End state:
        - I2 executing, I3 stalled in Operand Read (RAW on F5), I4 stalled in Operand Read (RAW on F7), I5 cannot dispatch
        - Integer unit free, Multiplier unit reserved by I2, Adder unit reserved by I3, Divider unit reserved by I4
        - F5(I2), F7(I3) and F9(I4) pending. F3 ready. Other registers unchanged.


Cycle 12:
- I2: Multiply F5 using operands F3 and F7
        - Commits F5
- I3: Add F7 using operands F5 and F9  
        - F9 available but F5 is pending
        - Operand read stalls
- I4: Divide F9 using operands F7 and F3 
        - F3 is available but F7 is pending by I3
        - Operand read stalls
- I5: Subtract to produce F11 using F9 and F5  
        - Adder not available
- End state:
        - I2 commits F5 and leaves, I3 stalled in Operand Read (RAW on F5), I4 stalled in Operand Read (RAW on F7), I5 cannot dispatch
        - Integer unit free, Multiplier unit free, Adder unit reserved by I3, Divider unit reserved by I4
        - F7(I3) and F9(I4) pending. F3 and F5 ready. Other registers unchanged.


Cycle 13:
- I3: Add F7 using operands F5 and F9  
        - F5 and F9 is available
        - Successfully read operands
- I4: Divide F9 using operands F7 and F3 
        - F3 is available but F7 is pending by I3
        - Operand read stalls
- I5: Subtract to produce F11 using F9 and F5  
        - Adder not available
- End state:
        - I3 successfully read operands, I4 stalled in Operand Read (RAW on F7), I5 cannot dispatch
        - Integer unit free, Multiplier unit free, Adder unit reserved by I3, Divider unit reserved by I4
        - F7(I3) and F9(I4) pending. F3 and F5 ready. Other registers unchanged.


Cycle 14-17:
- I3: Add F7 using operands F5 and F9  
        - Starts execution
        - Will execute for 4 cycles
        - Will complete execution by the end of cycle 17
- I4: Divide F9 using operands F7 and F3 
        - F3 is available but F7 is pending by I3
        - Operand read stalls
- I5: Subtract to produce F11 using F9 and F5  
        - Adder not available
- End state:
        - I3 executing, I4 stalled in Operand Read (RAW on F7), I5 cannot dispatch
        - Integer unit free, Multiplier unit free, Adder unit reserved by I3, Divider unit reserved by I4
        - F7(I3) and F9(I4) pending. F3 and F5 ready. Other registers unchanged.


Cycle 18:
- I3: Add F7 using operands F5 and F9  
        - Commits F7
- I4: Divide F9 using operands F7 and F3 
        - F3 is available but F7 is pending by I3
        - Operand read stalls
- I5: Subtract to produce F11 using F9 and F5  
        - Adder not available
- End state:
        - I3 commits F7 and leaves, I4 stalled in Operand Read (RAW on F7), I5 cannot dispatch
        - Integer unit free, Multiplier unit free, Adder unit free, Divider unit reserved by I4
        - F9(I4) pending. F3, F5 and F7 ready. Other registers unchanged.


Cycle 19:
- I4: Divide F9 using operands F7 and F3 
        - F3 and F7 both available
        - Successfully acquire operands
- I5: Subtract to produce F11 using F9 and F5  
        - Adder available
        - Dispatches I5
- End state:
        - I4 successfully acquire operands, I5 dispatched
        - Integer unit free, Multiplier unit free, Adder reserved by I5, Divider unit reserved by I4
        - F9(I4), F11(I5) pending. F3, F5 and F7 ready. Other registers unchanged.


Cycle 20:
- I4: Divide F9 using operands F7 and F3 
        - Starts execution
        - Will execute for 9 cycles
        - Will complete execution by 28 
- I5: Subtract to produce F11 using F9 and F5  
        - F5 is available but F9 is pending 
        - Operand read stalls
- I6: Load F1 from the memory location addressed by R5
        - Integer unit available
        - Dispatches I6
- End state:
        - I4 starts execution, I5 stalled in Operand Read (RAW on F9), I6 dispatched
        - Integer reserved by I6, Multiplier unit free, Adder reserved by I5, Divider unit reserved by I4
        - F1(I6), F9(I4), F11(I5) pending. F3, F5 and F7 ready. Other registers unchanged.


Cycle 21:
- I4: Divide F9 using operands F7 and F3 
        - Executing
- I5: Subtract to produce F11 using F9 and F5  
        - F5 is available but F9 is pending 
        - Operand read stalls
- I6: Load F1 from the memory location addressed by R5
        - R5 available 
        - Successfully acquire operands
- I7: Multiply F3 using operands F1 and F11  
        - Multiplier unit free
        - I7 dispatches
- End state:
        - I4 executing, I5 stalled in Operand Read (RAW on F9), I6 successfully acquire operands, I7 dispatched
        - Integer reserved by I6, Multiplier reserved by I7, Adder reserved by I5, Divider unit reserved by I4
        - F1(I6), F3(I7), F9(I4), F11(I5) pending. F5 and F7 ready. Other registers unchanged.


Cycle 22:
- I4: Divide F9 using operands F7 and F3 
        - Executing
- I5: Subtract to produce F11 using F9 and F5  
        - F5 is available but F9 is pending 
        - Operand read stalls
- I6: Load F1 from the memory location addressed by R5
        - Starts execution 
        - completes execution by the end of cycle
- I7: Multiply F3 using operands F1 and F11  
        - F1 and F11 both are not available.
        - Operand read stalls
- I8: Add F5 using operands F3 and F7 
        - Adder not available
        - Cannot dispatch
- End state:
        - I4 executing, I5 stalled in Operand Read (RAW on F9), I6 executing, I7 stalled in Operand Read (RAW on F1 and F11), I8 not dispatched
        - Integer reserved by I6, Multiplier reserved by I7, Adder reserved by I5, Divider unit reserved by I4
        - F1(I6), F3(I7), F9(I4), F11(I5) pending. F5 and F7 ready. Other registers unchanged.


Cycle 23:
- I4: Divide F9 using operands F7 and F3 
        - Executing
- I5: Subtract to produce F11 using F9 and F5  
        - F5 is available but F9 is pending 
        - Operand read stalls
- I6: Load F1 from the memory location addressed by R5
        - Commits F1
- I7: Multiply F3 using operands F1 and F11  
        - F1 is available but F11 is not available.
        - Operand read stalls
- I8: Add F5 using operands F3 and F7 
        - Adder not available
        - Cannot dispatch
- End state:
        - I4 executing, I5 stalled in Operand Read (RAW on F9), I6 commit F1 and leaves, I7 stalled in Operand Read (RAW on F1 and F11), I8 not dispatched
        - Integer unit free, Multiplier reserved by I7, Adder reserved by I5, Divider unit reserved by I4
        - F3(I7), F9(I4), F11(I5) pending. F1, F5 and F7 ready. Other registers unchanged.


Cycle 24-28:
- I4: Divide F9 using operands F7 and F3 
        - Executing
        - Completes execution in cycle 28
- I5: Subtract to produce F11 using F9 and F5  
        - F5 is available but F9 is pending 
        - Operand read stalls
- I7: Multiply F3 using operands F1 and F11  
        - F1 is available but F11 is not available.
        - Operand read stalls
- I8: Add F5 using operands F3 and F7 
        - Adder not available
        - Cannot dispatch
- End state:
        - I4 executing, I5 stalled in Operand Read (RAW on F9), I7 stalled in Operand Read (RAW on F1 and F11), I8 not dispatched
        - Integer unit free, Multiplier reserved by I7, Adder reserved by I5, Divider unit reserved by I4
        - F3(I7), F9(I4), F11(I5) pending. F1, F5 and F7 ready. Other registers unchanged.


Cycle 29:
- I4: Divide F9 using operands F7 and F3 
        - Commits F9
- I5: Subtract to produce F11 using F9 and F5  
        - F5 is available but F9 is pending 
        - Operand read stalls
- I7: Multiply F3 using operands F1 and F11  
        - F1 is available but F11 is not available.
        - Operand read stalls
- I8: Add F5 using operands F3 and F7 
        - Adder not available
        - Cannot dispatch
- End state:
        - I4 commits F9 and leaves, I5 stalled in Operand Read (RAW on F9), I7 stalled in Operand Read (RAW on F1 and F11), I8 not dispatched
        - Integer unit free, Multiplier reserved by I7, Adder reserved by I5, Divider unit free
        - F3(I7), F11(I5) pending. F1, F5, F7 and F9 ready. Other registers unchanged.


Cycle 30:
- I5: Subtract to produce F11 using F9 and F5  
        - F5 and F9 both are available
        - Successfully acquire operands
- I7: Multiply F3 using operands F1 and F11  
        - F1 is available but F11 is not available.
        - Operand read stalls
- I8: Add F5 using operands F3 and F7 
        - Adder not available
        - Cannot dispatch
- End state:
        - I5 successfully acquire operands, I7 stalled in Operand Read (RAW on F1 and F11), I8 not dispatched
        - Integer unit free, Multiplier reserved by I7, Adder reserved by I5, Divider unit free
        - F3(I7), F11(I5) pending. F1, F5, F7 and F9 ready. Other registers unchanged.


Cycle 31-34:
- I5: Subtract to produce F11 using F9 and F5  
        - Execution starts
        - Will be executing for 4 cycles
        - Will be completing execution by the end of cycle 34
- I7: Multiply F3 using operands F1 and F11  
        - F1 is available but F11 is not available.
        - Operand read stalls
- I8: Add F5 using operands F3 and F7 
        - Adder not available
        - Cannot dispatch
- End state:
        - I5 starts execution, I7 stalled in Operand Read (RAW on F1 and F11), I8 not dispatched
        - Integer unit free, Multiplier reserved by I7, Adder reserved by I5, Divider unit free
        - F3(I7), F11(I5) pending. F1, F5, F7 and F9 ready. Other registers unchanged.



Cycle 35:
- I5: Subtract to produce F11 using F9 and F5  
        - Commit F11
- I7: Multiply F3 using operands F1 and F11  
        - F1 is available but F11 is not available.
        - Operand read stalls
- I8: Add F5 using operands F3 and F7 
        - Adder not available
        - Cannot dispatch
- End state:
        - I5 commit F11 and leaves, I7 stalled in Operand Read (RAW on F1 and F11), I8 not dispatched
        - Integer unit free, Multiplier reserved by I7, Adder unit free, Divider unit free
        - F3(I7) pending. F1, F5, F7, F9 and F11 ready. Other registers unchanged.


Cycle 36:
- I7: Multiply F3 using operands F1 and F11  
        - F1 and F11 both are available.
        - Successfully acquire operands
- I8: Add F5 using operands F3 and F7 
        - Adder is available
        - I8 dispatches
- End state:
        - I7 successfully acquire operands, I8 dispatched
        - Integer unit free, Multiplier reserved by I7, Adder reserved by I8, Divider unit free
        - F3(I7), F5(I8) pending. F1, F7 and F9 ready. Other registers unchanged.


Cycle 37:
- I7: Multiply F3 using operands F1 and F11  
        - Starts execution
        - Will be executing for 6 cycles
        - Will complete execution by cycle 42
- I8: Add F5 using operands F3 and F7 
        - F7 is available but F3 is pending
        - Operand read stalls
- I9: Divide F7 using operands F5 and F1 
        - Divider unit free
        - I9 dispatches
- End state:
        - I7 starts execution, I8 stalled in Operand Read (RAW on F3), I9 dispatches
        - Integer unit free, Multiplier reserved by I7, Adder reserved by I8, Divider reserved by I9
        - F3(I7), F5(I8), F7(I9) pending. F1 and F9 ready. Other registers unchanged.



Cycle 38:
- I7: Multiply F3 using operands F1 and F11  
        - Executing
- I8: Add F5 using operands F3 and F7 
        - F7 is available but F3 is pending
        - Operand read stalls
- I9: Divide F7 using operands F5 and F1 
        - F1 is available but F5 is pending
        - Operand read stalls
- I10: Subtract to produce F9 using F7 and F3 
        - Adder not available
        - Cannot dispatch I10
- End state:
        - I7 executing, I8 stalled in Operand Read (RAW on F3), I9 stalled in Operand Read (RAW on F5), I0 cannot dispatch
        - Integer unit free, Multiplier reserved by I7, Adder reserved by I8, Divider reserved by I9
        - F3(I7), F5(I8), F7(I9) pending. F1 and F9 ready. Other registers unchanged.


Cycle 39-42:
- I7: Multiply F3 using operands F1 and F11  
        - Executing
        - Completes execution by the end of cycle 42
- I8: Add F5 using operands F3 and F7 
        - F7 is available but F3 is pending
        - Operand read stalls
- I9: Divide F7 using operands F5 and F1 
        - F1 is available but F5 is pending
        - Operand read stalls
- I10: Subtract to produce F9 using F7 and F3 
        - Adder not available
        - Cannot dispatch I10
- End state:
        - I7 completes execution by the end of cycle 42, I8 stalled in Operand Read (RAW on F3), I9 stalled in Operand Read (RAW on F5), I0 cannot dispatch
        - Integer unit free, Multiplier reserved by I7, Adder reserved by I8, Divider reserved by I9
        - F3(I7), F5(I8), F7(I9) pending. F1 and F9 ready. Other registers unchanged.


Cycle 43:
- I7: Multiply F3 using operands F1 and F11  
        - Commits F3
- I8: Add F5 using operands F3 and F7 
        - F7 is available but F3 is pending
        - Operand read stalls
- I9: Divide F7 using operands F5 and F1 
        - F1 is available but F5 is pending
        - Operand read stalls
- I10: Subtract to produce F9 using F7 and F3 
        - Adder not available
        - Cannot dispatch I10
- End state:
        - I7 commits F3 and leaves, I8 stalled in Operand Read (RAW on F3), I9 stalled in Operand Read (RAW on F5), I0 cannot dispatch
        - Integer unit free, Multiplier unit free, Adder reserved by I8, Divider reserved by I9
        - F5(I8), F7(I9) pending. F1, F3 and F9 ready. Other registers unchanged.


Cycle 44:
- I8: Add F5 using operands F3 and F7 
        - F3 and F7 are available
        - Successfully acquire operands
- I9: Divide F7 using operands F5 and F1 
        - F1 is available but F5 is pending
        - Operand read stalls
- I10: Subtract to produce F9 using F7 and F3 
        - Adder not available
        - Cannot dispatch I10
- End state:
        - I8 successfully acquire operands, I9 stalled in Operand Read (RAW on F5), I10 cannot dispatch
        - Integer unit free, Multiplier unit free, Adder reserved by I8, Divider reserved by I9
        - F5(I8), F7(I9) pending. F1, F3 and F9 ready. Other registers unchanged.


Cycle 45-48:
- I8: Add F5 using operands F3 and F7 
        - Starts execution
        - Will execute for 4 cycles
        - Will complete execution by the end of cycle 48
- I9: Divide F7 using operands F5 and F1 
        - F1 is available but F5 is pending
        - Operand read stalls
- I10: Subtract to produce F9 using F7 and F3 
        - Adder not available
        - Cannot dispatch I10
- End state:
        - I8 executing, I9 stalled in Operand Read (RAW on F5), I10 cannot dispatch
        - Integer unit free, Multiplier unit free, Adder reserved by I8, Divider reserved by I9
        - F5(I8), F7(I9) pending. F1, F3 and F9 ready. Other registers unchanged.


Cycle 49:
- I8: Add F5 using operands F3 and F7 
        - Commits F5
- I9: Divide F7 using operands F5 and F1 
        - F1 is available but F5 is pending
        - Operand read stalls
- I10: Subtract to produce F9 using F7 and F3 
        - Adder not available
        - Cannot dispatch I10
- End state:
        - I8 commits F5 and leaves, I9 stalled in Operand Read (RAW on F5), I10 cannot dispatch
        - Integer unit free, Multiplier unit free, Adder unit free, Divider reserved by I9
        - F7(I9) pending. F1, F3, F5 and F9 ready. Other registers unchanged.


Cycle 50:
- I9: Divide F7 using operands F5 and F1 
        - F1 and F5 both are available
        - Successfully acquire operands
- I10: Subtract to produce F9 using F7 and F3 
        - Adder is available
        - I10 dispatches
- End state:
        - I9 successfully acquire operands, I0 dispatched
        - Integer unit free, Multiplier unit free, Adder unit reserved by I10, Divider reserved by I9
        - F7(I9), F9(I10) pending. F1, F3, F5 ready. Other registers unchanged.


Cycle 51-59:
- I9: Divide F7 using operands F5 and F1 
        - Starts execution 
        - Will execute for 9 cycles
        - Will complete execution by the end of cycle 59
- I10: Subtract to produce F9 using F7 and F3 
        - F3 is available but F7 is pending
        - Operand read stalls
- End state:
        - I9 starts execution, I0 stalled in Operand Read (RAW on F7)
        - Integer unit free, Multiplier unit free, Adder unit reserved by I10, Divider reserved by I9
        - F7(I9), F9(I10) pending. F1, F3, F5 ready. Other registers unchanged.


Cycle 60:
- I9: Divide F7 using operands F5 and F1 
        - Commits F7
- I10: Subtract to produce F9 using F7 and F3 
        - F3 is available but F7 is pending
        - Operand read stalls
- End state:
        - I9 commit F7 and leaves, I0 stalled in Operand Read (RAW on F7)
        - Integer unit free, Multiplier unit free, Adder unit reserved by I10, Divider unit free
        - F9(I10) pending. F1, F3, F5, F7 ready. Other registers unchanged.


Cycle 61:
- I10: Subtract to produce F9 using F7 and F3 
        - F3 and F7 both are available
        - Successfully acquire operands
- End state:
        - I0 successfully acquire operands
        - Integer unit free, Multiplier unit free, Adder unit reserved by I10, Divider unit free
        - F9(I10) pending. F1, F3, F5, F7 ready. Other registers unchanged.


Cycle 62-65:
- I10: Subtract to produce F9 using F7 and F3 
        - Starts execution
        - Will be executing for 4 cycles
        - Will complete execution by cycle 65 
- End state:
        - I0 executing
        - Integer unit free, Multiplier unit free, Adder unit reserved by I10, Divider unit free
        - F9(I10) pending. F1, F3, F5, F7 ready. Other registers unchanged.


Cycle 66:
- I10: Subtract to produce F9 using F7 and F3 
        - Commit F9
- End state:
        - I0 commits F9 and leavs
        - Integer unit free, Multiplier unit free, Adder unit free, Divider unit free
        - F1, F3, F5, F7 and F9 ready. Other registers unchanged.



Final answers 
1. The cycle at which the final instruction finishes committing its result 
Cycle 66

2. The total of all dispatch cycle numbers  
1 + 2 + 3 + 4 + 19 + 20 + 21 + 36 + 37 + 50 = 193

3. The total of all result-commit cycle numbers  
339

4. The cumulative number of stall cycles caused by WAW conflicts  
0

5. The commit cycle of instruction I6  
23

6. The earliest cycle at which the integer execution unit becomes permanently idle  
24

7. The maximum number of instructions simultaneously present in the system (issued but not yet committed)  
5

8. The instruction that experiences the longest continuous stall period
I4

9. The total number of cycles during which no instruction is able to dispatch  
56

10. The average execution-unit utilization across all functional units over the entire timeline  
| Unit        | Busy cycles |
| ----------- | ----------- |
| Integer     | 2           |
| FP Add/Sub  | 16                    |
| FP Multiply | 12          |
| FP Divide   | 18          |

Total possible = 4 × 66 = 264
Utilization = 48/264 = 18.2%