WGU C952 Computer Architecture - Ch. 5 - Participation Activities Complete Questions And Answers

WGU C952 Computer Architecture - Ch. 5 - Participation Activities Complete Questions And Answers Q.Consider the first three steps for a typical LEGv8 instruction. 1st step 2nd step 3rd step for memory-reference instructions 3rd step for arithmetic-logic instructions 3rd step for branch instructions - ANSWER-1. Fetch instruction from memory - Every instruction must first be fetched from memory, based on the value of the program counter. 2. Read register(s) - Every instruction reads one or two registers. 3a. Use ALU for address calculation - determines what memory address to access. 3b. Use ALU for operation execution - instruction's operation like add or subtract is carried out by the ALU 3c. Use ALU for comparisons - result of the comparison determines whether the branch should be taken Q.A datapath element whose output values depend only on the present input values is called a _____ element. - ANSWER-combinational The output values depend solely on the present "combination" of input values. Q.A datapath element that has internal storage is called a _____ element. - ANSWER-state The stored values represents the element's state. Q.Element F has input b and output z, originally 0. If b changes from 0 to 1, z changes to 1 and stays 1 even after b returns to 0. If b later changes from 0 to 1 again, z changes back to 0. And so on.Element F is a _____ element. - ANSWER-state The output z is not solely dependent on the present value of b. For example, when b is 0, sometimes z is 0, and sometimes z is 1. Rather, the element has an internal state of either 0 or 1 that is being output to z. Input b can change that state. Q.An ALU is a _____ element. - ANSWER-combinational An ALU does not store anything. Rather, given input values, and ALU operates on those values to generate output values. Those output values only depend on the present combination of input values. Q.A register is a _____ element. - ANSWER-state A register stores bits, and thus has state. Q.A clock input is present on a _____ element. - ANSWER-state The clock determines when data can be written into the element's internal storage. Q.A sequential element is another name for a _____ element. - ANSWER-state The output is dependent on the "sequence" of previous input values, and not just the present combination of input values. Q.A rising clock edge refers to the clock changing from _____. - ANSWER-0 to 1 0 to 1 is "rising" due to changing from a lower value (0) to a higher value (1). Q.Let's say, state element 1 gets written with a new value on the first rising clock edge, causing the combinational logic to output a new value _____. - ANSWER-after some amount of time Logic has some delay, so the logic's new output will only appear after some time passes, typically after a few nanoseconds. Q.Let's say, a rising clock edge writes a new state element 1 value, serving as input to the combinational logic. If the logic requires 5 ns to output a new value, designers should ensure that rising clock edges are separated by _____. - ANSWER-more than 5s By separating rising clock edges by more than 5 ns, the designer ensures the logic's output is ready and waiting to be written to state element 2 when the next rising edge occurs. Q.What happens just after a rising clock edge writes a new value to the element? - ANSWER-The logic calculates a new value that then waits at the state element's input for the next rising edge. The next rising edge occur sufficiently long after the previous rising edge, to ensure the logic's new value is ready.