Quiz 8.5

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: Section 8.5

  1. When doing indirect store in the CSC-1 computer, which register contains the data to be stored into memory?
PC
IR
A
S

  1. When doing indirect store in the CSC-1 computer, which register contains the address of where to store the data?
PC
IR
A
S

  1. What is the CSC-1's indirect load instruction?
LDI
LOD
LDS
LDA

  1. What do we call a variable in memory whose contents is an address?
pointer
accumulator
secondary
indirection

  1. How does the A register communicate with the S register?
through memory
through the MBR
by a set of direct wires between them
they can't communicate Questions 6 and 7 deal with the following fragment of CSC-1 program:
GIFs/program1.gif

  1. What will be in the A register after the LDS instruction is performed?
62
701
815
194

  1. What will be in S after LDS is performed?
62
701
815
194 Questions 8 and 9 deal with the following fragment of CSC-1 program:
GIFs/program2.gif

  1. Which memory cell changes when this program fragment is completed?
5249
6401
7300
7400
8279

  1. What value will be in that memory cell (the one that is changed)?
22
30
7300
7400

  1. Very early computers actually changed their instructions while running! Which of the following program self-modifications would the CSC-1 have to do to achieve what indirect loading does (without program self-modification) via the LDS instruction?
change the opcode of a LOD instruction to LDI
change the operand of a LOD instruction
change the operand of an ADD instruction
change the operand of an LDS instruction

  1. What addressing-related bug often happens in programs, causing them to crash at run-time?
the memory gets an illegal data value to store
the instruction decoder gets an invalid opcode
a counter variable experiences arithmetic overflow
a loop goes too far and tries to access non-existent elements of an array

  1. What is the name of the addressing-related bug that was discussed in the above question?
page fault
processor fault
memory fault
bus fault