Lesson 2--Review of VLIW

Question 1

RISC

Answer 1

• -Simple, fewer instructions
• -Fixed length instructions
• -Complexity in compiler
• -Only LOAD/STORE instructions access memory
• -Few addressing modes

Question 2

CISC

Answer 2

• -many complex instructions
• -variable length instructions
• -complexity in microcode
• -many instructions access memory
• -many accessing modes

Question 3

RISC Characteristics

Answer 3

• -simpler hardware
• -lower per-chip cost
• -code expansion can be a problem

Question 4

CISC Characteristics

Answer 4

• -makes more efficient use of a slow memory
• -requires less complicated compiler
• -instructions take different amounts of time to execute

Question 5

VLIW

Answer 5

Variable Length Instruction Word

Multiple small instructions in one large instruction

Question 6

VLIW Pros

Answer 6

Lots of registers
Lower number of transistors than other designs
Can take advantage of size efficiencies, price, power consumption

Question 7

VLIW Cons

Answer 7

not backward compatible or easily upgradable

Question 8

Instruction Scheduling: VLIW vs Superscalar

Answer 8

Superscalar: Done by hardware at run-time
VLIW: Done by compiler

Question 9

Data Dependency: VLIW vs Superscalar

Answer 9

Superscalar: Checked and resolved by hardware
VLIW: Checked by compiler

Question 10

The hardware handles all register renaming

Answer 10

Superscalar

Question 11

A high bandwidth between instruction cache and fetch unit

Answer 11

VLIW

Question 12

The hardware tries to issue as many instructions in parallel as possible

Answer 12

Superscalar

Question 13

Power consumption is large

Answer 13

Superscalar

Question 14

A good compiler can detect parallelism throughout the program

Answer 14

VLIW