Question

Computer architecture

Question 28 Answer the following about the two instructions below. il to, (50) sc ti, OC50) # Load Linked # Store Conditional Select True/False (T/F) for each statement The instructions Il/sc are used when we need to load/store the data fast. [Select) The Il/sc instructions can be used to implement a mutex. [Select] If sc cannot be done atomically with II, then sc is cancelled. [Select) For sc instruction above, register so changes to indicate the feedback [Select ] F T

Answer 1

1.)

• The load-link/store-conditional operation is not really used to load and store data. It is used to implement syncronization in a program by acquiring a lock through LL operation. The sc only store if no other store operation is performed after the previous LL operatin
• Answer: False

2.)

• Yes, LL/SC instruction can be used to implement mutex. The syncronization is done as expplained in the first answer:
• Answer: True

3.)

• Yes, sc is cancelled when store operation cannot be performed automatically with LL. It happens when a store operation took place in s0 after the LL operation.
• Answer: True

4.)

• Well, s0 does change on store operation but, the feedback is indiacated by the return value from sc operation.
• The value is 1 if sc succeds, and it is 0 if it fails.
• Answer: False.