Quiz 7.4

DIRECTIONS: Read each question carefully. Then click on the dot next to the answer that most closely fits the question. Try to answer all questions on this quiz and when you are done, click on the grade me button at the bottom.

Coverage: Sections 7.5 and 7.6

  1. Which name means the same thing as fetch/decode/execute cycle?
machine cycle
instruction cycle
both

  1. What is the order of the four basic stages in the CSC-1's fetch/decode/execute cycle?
instruction fetch; operation decode; operand fetch; execute stage
instruction fetch; operation fetch; operand decode; execute stage
instruction fetch; operation fetch; execute stage; storeback stage

  1. During which stage is the IR set?
execute stage
operation decode
operand fetch
instruction fetch

  1. Which instruction skips the operand fetch stage?
ADD
OR
SHR
SUB

  1. Which of the following is not a synonym for jump?
branch
goto
leap

  1. When the ADD instruction runs, when does the ALU get to do its work?
execute stage
operation decode
operand fetch
instruction fetch

  1. How is the operand of a jump instruction different than the operand of an ADD or SUB instruction?
it requires only 8 bits, not 16
memory contents are fetched during the execute stage, not the operand fetch stage
nothing in memory at that address is fetched
the instruction decoder delays setting the proper instruction wire high until operand fetch stage

  1. What in the CSC-1 gets changed by the NOP instruction?
absolutely nothing
the A register
the S register
the PC register

  1. The following picture shows the CSC-1 with a program loaded into memory. What is the very next thing that will get done?
    GIFs/start_of_cycle.gif
MAR will get the value 257
257 will be sent to IR
MBR will get the value 257
11 will be added to 23 in the A register

  1. How many times does a value get fetched from memory during an ADD instruction in the CSC-1?
only once
twice
it depends on the data

  1. When a value resides in a register, as 23 does in the A register in the picture above, what keeps that value from getting copied into all other registers which connect to A?
the multiplexors on the other registers
the load control wires on the other registers
the load control wire on A; it must go high to permit A to copy its value out
other control wires not shown in the block diagram