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There are basically 2 things i need to figure out.

  1. Timing charts

  2. Total cycles for the 3 mips instructions.

  3. How does it differ when it is branch taken and branch not taken for a "predict not taken branch prediction"

Characteristics

  • Full forwarding paths

  • Predict not taken branch prediction - branch not taken

  • Early branching

  • Include write back stage of last instruction

Branch not taken

| Instructions            | 1  | 2  | 3  | 4  | 5  | 6  | 7  | 8  | 9  | 10  |
|:------------------------|---:|---:|---:|---:|---:|---:|---:|---:|---:|----:|
| slt $t8, $t0, $t9       | F  | D  | E  | M  | W  |    |    |    |    |     |
| beq $t8, $zero, end     |    | F  | D  | D  | E  | M  | W  |    |    |     | 
| sll $t2, t0, 2          |    |    | F  | F  | D  | E  | M  | W  |    |     |

Total cycles: 8

Branch taken

| Instructions            | 1  | 2  | 3  | 4  | 5  | 6  | 7  | 8  | 9  | 10  |
|:------------------------|---:|---:|---:|---:|---:|---:|---:|---:|---:|----:|
| slt $t8, $t0, $t9       | F  | D  | E  | M  | W  |    |    |    |    |     |
| beq $t8, $zero, end     |    | F  | D  | D  | E  | M  | W  |    |    |     | 
| sll $t2, t0, 2          |    |    |    |    |    |    |    |    |    |     |
| ... end here            |    |    |    |    |    |    |    |    |    |     |

The answer should be okay for slt since it's the first instruction.

The confusing part is the beq and sll. I am not too sure what stage are they in for the timings.

Could anyone share more on how to complete the timing charts for beq and sll portion?

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