Data, Information and Memory Flashcards
What is a memory address?
A unique individual location in memory that stores 1 byte of information.
What are variables?
Data created by computer programs and stored in memory at a specific address where they can later be accessed.
How does the write function operate?
To store (Write) a value in memory, the CPU must write the value in the memory’s Data Register and the specify address where in memory it is to be stored in the Address Register. The CPU must also indicate a Write operation to memory using the R/W and control signals(wires).
How does the read function operate?
To access (Read) a value in memory, the CPU must put the address of the location in memory to be read into the Address Register. The CPU must also indicate a Read operation to memory using the R/W and control signals. The memory responds by putting the contents of the location into the Data Register.
What is machine code?
Programs in memory in binary is such that the program code can be directly understood and executed by the processor.
What is a compiler?
Takes a HLL and converts it into the specific machine code of the processor that will execute it. Also generates a more human-readable form of the machine code specified called assembly language.
What is the Von Neumann Architecture?
A programmable machine that can store, retrieve and process data. Consists of Input/Output, storage and CPU.
List the CPU components.
-Registers
-Control Unit
-ALU Arithmetic Logic Unit
What is the role of the register?
Store data in CPU (They are referenced by name not address e.g. Accumulator A.)
Update of registers controlled by Control Unit.
Data can come from or go to memory, ALU or other registers.
What is the role of the ALU?
Performs operations, usually 2 inputs and 1 output per operation.
Controlled by signals from Control Unit.
What are the functions and role of the Control Unit?
Control Unit:
Control Lines
Loads instructions from memory.
Decodes the instructions
Program Counter
What is the memory address register?
contains the address of the memory location being referenced. The size of the address-register determines the range of addresses for memory.
What is the memory data register?
contains the contents of the address that is read or written. Data-bus size called the Word size determines the maximum amount of data that transferred in 1 read or write operation.
What are control signals?
Synchronise the transfer of data to/from CPU from/to memory.
What is the instruction register?
holds the instruction currently being fetched from memory while it is being acquired from memory
What is the status regitser?
The register is updated after the execution of every instruction, reflecting the status of the result.
Half carry (H) - set if there was a carry from bit 3 to bit 4 of the result when the result was calculated.
Interrupt mask (I) - set if the IRQ interrupt is disabled.
Negative (N) - set if the most significant bit of the result is set.
Zero (Z) - Set if the result is zero.
What is the index register?
register usually used for temporary storage or as an index when indexed addressing is used.
What is the instruction set?
The set of all possible instructions reference by op-codes that can be performed by the processor.
