Chapter 1

Question 1

Explain the idea behind RISC(SRC) computer

Answer 1

• Uses instruction of fixed size - 32 bit
• Most instruction take same time to fetch
• instruction set simple and small
• Less addressing modes as most operations are registered based.
• Compiler design is complex
• Total size of program is large as many instructions are required to perform a task - because instructions are simple
• Instructions uses fixed number of operands
• Ideal for processors performing dedicated operations
• Since instructions are simple, they can be decoded by hardware control unit.
• Execution speed is faster as most operations are register based
• Since number of cycles per instruction is fixed it gives better degree of pipe-lining.

Question 2

Write KB,MB,GB,TB in base 10

Hint: 2^10 ~ 10^3

Answer 2

• KB - 10^3
• MB - 10^6
• GB - 10^9
• TB - 10^12

Question 3

• milli, nano, micro, pico*
• GB, TB, MB, KB*

Answer 3

• milli = 10^-3. KB = 10^3*
• micro = 10^-6. MB = 10^6*
• nano = 10^-9. GB = 10^9*
• pico = 10^-12. TB = 10^12*

Question 4

Bit**, Nibble, Byte, word, double word, long word, Hertz

Answer 4

Bit - basic unit to store current - 1 or 0.

Nibble - 4 bits - storing a digit of a number

Byte - 8 bits

word - 2 bytes, 16 bits

double word - 4 bytes, 32 bits

long word - 8 bytes , 64 bits

Hertz - one cycle per second

Question 5

What is assembler?

Answer 5

Computer program that translates with a one-to-one mapping, assembly to machine language.

Question 6

What can you tell me about the PC register?

What can you tell me about the IR register?

Why both are needed?

Answer 6

• PC points to the address of the next instruction to be executed.
• IR points to the current encoded instruction.
• Upon fetching the current instruction to be saved on IR register, PC is incremented by 1 (which is 4 bytes - an address size). Then the instruction is decoded and executed.
• We need both because we can’t keep track on the sequence of instructions and also save their values with merely one register.

Question 7

What is special about the MA and MD registers?

Answer 7

_They access memory directly_

• MD - save and store memory data
• MA - only save memory data

The rest of the 32 registers are used to store data temporarily in the cpu, before the desired data is saved to memory.

Question 8

What is the ALU unit?

Answer 8

Arithmatic logic unit

Two entrances A,B which are used as operators, on which we perform an arithmatic operaion.