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Flashcards in The Processor ( 2 ) Deck (16):
1

How does increasing word length affect the speed of the processor?

• Word size of the computer is the number of bits that the CPU can process simultaneously.
• Increasing the number of bits that can be handled in one pulse of the clock.

2

What is a word?

Collection of bits that can be addressed and manipulated as a single unit

3

What is the word size?

• Word size of the computer is the number of bits that the CPU can process simultaneously.

4

How does increasing cores increase processor speed?

• Each core is able to process a different instruction at the same time with its own fetch execute cycle, making it multiple times faster.

5

what is cache?

• Very small amount of very fast memory inside or near the CPU.
• When an instruction is fetched from main memory it is copied into the cache so if its needed again soon after it can be fetched from the cache, this is quicker than going back to main memory, as cache fills up unused instructions/data are replaced with more frequently used ones.

6

How does cache memory work?

• When an instruction is fetched from main memory it is copied into the cache so if its needed again soon after it can be fetched from the cache, this is quicker than going back to main memory, as cache fills up unused instructions/data are replaced with more frequently used ones.
• Cache can be accessed much quicker than main memory, so programs run faster.

7

What is an interrupt?

A signal sent by a software program or hardware device to the CPU.

8

When does a software interrupt occur?

When an application program terminates or requests certain services from the OS system.

9

When may a hardware interrupt occur?

When an I/O operation is complete or an error occurs.

10

What happens when the CPU receives an interrupt signal?

• Suspends execution of the running program or process
• Puts values of each register and PC onto the system stack
• An interrupt service routine is called to deal with the interrupt.
• Once an interrupt has been serviced, the original values of the registers are retrieved from the stack and the fetch execute cycle resumes from the point that it left off, a test for the presence of interrupts is carried out at the end of each instruction cycle.

11

What occurs when an interrupt is serviced?

• Once an interrupt has been serviced, the original values of the registers are retrieved from the stack and the fetch execute cycle resumes from the point that it left off, a test for the presence of interrupts is carried out at the end of each instruction cycle.

12

What is called to deal with an interrupt?

An interrupt service routine.

13

What is immediate addressing?

• Value it follows is the actual data item
• Operand is the datum

14

What is direct addressing?

• Tells the CPU which address contains the data you want to access.
• Operand is the memory address or register number

15

What is the address?

Number that tells the computer where in memory to find a specific item of data.

16

What is an instruction set?

Complete set of all the instructions in machine code that can be recognised and executed by a central processing unit.