Question
You are building a basic CPU with a classic RISC pipeline. Answer the following about a seemingly harmless instruction you may use, for 10 points each.
[10m] Name this instruction, which can be used to implement a pipeline stall in certain architectures, including x86 and MIPS (“mips”). A “sled” or “slide” is named for this instruction, which does nothing when executed.
ANSWER: NOP [or no-op or NOOP or no operation]
[10h] In x86, a NOP is implemented by completing this atomic action equivalent to three MOV instructions on the AX register. This action can be used to implement a semaphore in x86 because it activates a bus lock.
ANSWER: XCHG [or exchanging two registers; accept descriptions of swapping the contents of two registers]
[10e] An attacker may install a NOP slide in memory while exploiting this type of vulnerability where the bounds of allocated memory are exceeded. A common coding website is named for this effect occurring to a stack.
ANSWER: overflow [or overrun; accept buffer overflow or buffer overrun; accept Stack Overflow]
<KJ, Other Science: Computer Science>
Summary
| 2023 ARCADIA at UC Berkeley | Premiere | Y | 2 | 15.00 | 100% | 50% | 0% |
| 2023 ARCADIA at Carleton University | Premiere | Y | 3 | 16.67 | 100% | 67% | 0% |
| 2023 ARCADIA at Claremont Colleges | Premiere | Y | 1 | 30.00 | 100% | 100% | 100% |
| 2023 ARCADIA at Duke | Emory, Duke, Yale | Y | 4 | 12.50 | 100% | 25% | 0% |
| 2023 ARCADIA at Emory | Emory, Duke, Yale | Y | 4 | 10.00 | 100% | 0% | 0% |
| 2023 ARCADIA at Imperial | Imperial | Y | 5 | 14.00 | 100% | 20% | 20% |
| 2023 ARCADIA at Indiana | Premiere | Y | 5 | 10.00 | 100% | 0% | 0% |
| 2023 ARCADIA at Ohio State | Ohio State, Texas | Y | 3 | 10.00 | 100% | 0% | 0% |
| 2023 ARCADIA Online | Maryland, Online | Y | 3 | 10.00 | 100% | 0% | 0% |
| 2023 ARCADIA at RIT | Premiere | Y | 2 | 15.00 | 100% | 0% | 50% |
| 2023 ARCADIA at Texas | Ohio State, Texas | Y | 3 | 10.00 | 100% | 0% | 0% |
| 2023 ARCADIA at WUSTL | Premiere | Y | 3 | 10.00 | 100% | 0% | 0% |
Data
| Duke | James Madison A | 0 | 0 | 10 | 10 |
| James Madison B | North Carolina A | 10 | 0 | 10 | 20 |
| South Carolina A | North Carolina B | 0 | 0 | 10 | 10 |
| South Carolina B | NC State | 0 | 0 | 10 | 10 |