Computer Architecture + Organisation Flashcards
1
Q
What is the control unit?
A
- Coordinates the CPU activities inside and outside the CPU
- Directs flow of data between the CPU and otherh devices
- In charge of the fetch execute decode cycle
- Sends read and write requrests to the memory through bus grants and interrupt requests
2
Q
What is the status register?
A
- Contains information about the state of the processor
- Individual bits are read or written by the machine code instructions executing on the processor
- These bits are flags which are set on or off and are checked at any points
3
Q
What is the clock in a CPU?
A
- Electronic unit that synchronsies related components y generating pulses at a constant rate
- Measured in Hertz
- Clock speed is the frequency at which the internal clock generates pulses
- The higher the clock rate the faster the performace of the CPU
4
Q
What is the ALU?
A
- Arithmetic Logic Unit
- Perform arithmetyic and logical operations on data
- Operations = + - X /
- Logic = XOR, AND, ect
- Bitewise shifts operations left and right
- Often uses general purpose reisters to temporarily hold the results of calculations
5
Q
What are general purpose registers?
A
- Tiny area off extremly fast memory locateed in the processor
- Data or control information is stored
- Can hold temp data for concurrent calculations
- The more registers the faster the CPU can operate
6
Q
What is the PC?
A
- Program counter
- Holds the address of the next instruction to be executed
- Could be the next instruction in a sequence of instructions
- If the current instuction is a command to retrive data from the memory
- Very close relationship with the MAR (memory adress register)
7
Q
What is the MAR?
A
Holds the address of memory location of
- Data
- INstructions
- Data to be fetched or where data needs to be written
Sends these address to memory down the address bus
8
Q
What is the MBR?
A
- Memory buffer register
- Store the data which is read from or written to memory
- All data must travel from memory must pass through the data buse and through the MBR
9
Q
What is the CIR?
A
- Curent instruction register
- Contents of MBR copied to the CIR
- Contains the operator and operands to make an instruction
10
Q
What is the Von Neumenn archecture?
A
- Shared memory space for instructions and data
- Instructions and data are stored in the same format
- Single control unit following a linear Fetch, Decode and Execute cycle
- Registers are used as fast access to instructions and data
11
Q
What is the Havard Architecture?
A
- Instruction and data are stored seperated in different memorty units
- Using its own buses
- Reading and writing data can be done simultaniously with fetching an instruction
- Used by RISC
12
Q
What happns in the fetch part of the FDE cycle?
A
13
Q
What is the decode part of the FDE cycle?
A
14
Q
What is the execute part of the FDE cycle?
A
15
Q
How does the CU effect CPU performance?
A
- CU relies on a clock
- The faster the clock the faster actions can be carried out on the CPU
- This generated more heat meaning coolings are needed
16
Q
How does cache effect CPU performance?
A
- Cache in the MDR is memory
- Which stores frequenctly accesed data
- This means a fetch isnt required to find that data saving time and resources
- The more caching memory the more efficient and quicker the CPU can be
17
Q
How does core count increase CPU
A
- the amount of cores
- The increase on simultanious proccesses that can be carried out
18
Q
What is a barcode reader?
A
- Used to read barcodes on products
- Trackng items and medical records
- Linear and 2D QR codes exsist
19
Q
How does a pen style barcode reader work?
A
- Light source with a photodiode place in the barcode
- The diode measures the intensity of light reflected back as it passes over ther barcode
- Generates a waveform
- Dark bars absorbed
- White bars reflect the light
- The wave form is then translated in a digital format
- This then is coded in and looked up
40
Q
What is immediate addressing?
A
- AKA immediate operand
- When the value in the address is part of the instruction is the actual value to be used
- Memory does not need to be searched for the values
- ADD 10 != Add whats in mem location 10
41
Q
What is direct addressing?
A
- Simple case
- Address in the memory iis where the value is that should be ued
- ADD 10 = Go to mem location 10 and add to Accumulator
47
Q
How are stacks used in interrupts?
A
- Tasks pushed and popped off the stack
- Allows for previous tasks to be resumed after interups are completed
- Process is doubled if higher proiority interups are also called
48
Q
What are the different types of interupts?
A
