Question

Assume that X1 is initialized to 11 and X2 is initialized to 22. Suppose you executed the code below on a version of the pipeline from COD Section 4.5 (An overview of pipelining) that does not handle data hazards (i.e., the programmer is responsible for addressing data hazards by inserting NOP instructions where necessary). What would the final values of registers X3 and X4 be

Answer 1

The final values of X3 and X4 cannot be determined without the specific code and an understanding of hazard-avoidance used. Data hazards in pipelines must be addressed to ensure correct computations.

Step-by-step explanation:

Without the code snippet provided, a precise answer cannot be given. However, in a pipelined processor that does not handle data hazards, instructions that access recently updated registers could execute before the modification has been written back. If such hazards are not resolved properly through techniques like adding NOP (No Operation) instructions or using other mitigation strategies, the final value of the registers (X3 and X4) may be incorrect or unpredictable.

To accurately determine the final values of X3 and X4, we would need to see the sequence of operations performed on these registers and ensure proper resolution of data hazards. If X1 and X2 are inputs to subsequent instructions affecting X3 and X4, we would need NOPs or other hazard-avoidance techniques to ensure that X3 and X4 are computed with the correct, updated values of X1 and X2.