Difficulty: Medium
Correct Answer: 11111100
Explanation:
Introduction / Context:
Intermediate states in serial loading depend on the initial contents, the input bit order, and the shift direction. Recognizing where the serial input enters helps avoid common off-by-one mistakes.
Given Data / Assumptions:
Concept / Approach:
At each clock, the current MSB receives the next serial bit, and all other bits shift one place toward the LSB. With the first two inputs both equal to 1, the upper two bits become 1 while the lower bits are previous contents shifted down.
Step-by-Step Solution:
Initial: 1 1 1 1 0 0 0 0.Clock 1 (in=1): 1 1 1 1 1 0 0 0.Clock 2 (in=1): 1 1 1 1 1 1 0 0 → 11111100.
Verification / Alternative check:
Quick simulation or a state table confirms that two leading 1s populate the top two positions while lower positions are the earlier upper bits shifting down.
Why Other Options Are Wrong:
11111000: corresponds to a different intermediate count of clocks.Other options either show no change, the final fully loaded pattern, or a wrong shift direction.
Common Pitfalls:
Misinterpreting where the serial input enters or counting the number of applied clocks incorrectly.
Final Answer:
11111100
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