Registers Flashcards
What is the arithmetic logic unit?
- Performs arithmetic and logical operations, such as fixed point and floating point arithmetic, logical operations (AND, OR, XOR) and shift operations.
- Inputs are from the internal bus and the accumulator, with outputs routed to one of the registers.
What is the control unit?
Main function is to fetch program instructions from memory, to decode them and to execute them serially.
What is the clock?
System clock sends a signal to each of the computer components on a regular basis to synchronise all of the computer operations
What is a Register?
A fast memory location that exists in the processor or the I/O controller. The computer consists of general purpose and dedicated registers
What are General Purpose Registers?
normally named R0, R1, R2, etc.) can be used to hold instructions and data temporarily
What are dedicated Registers?
are used by the processor to carry out a specific role
What is the accumulator?
Special register used as fast temporary storage by the ALU
What is the status Register?
Used to hold the status of various flags indicating e.g. positive result, negative result, carry bit used, overflow error, and interrupt status. The details of the SR storage are dependent upon the processor involved.
What is the program counter?
Register that holds the address of the next instruction to be fetched
What is the Memory Address Register (MAR)?
Holds the address of the current instruction being executed
What is the Memory buffer Register (MBR)?
Holds the instruction from the (MAR) and the associated data
What is the current instruction register (CIR)?
Used to store the instruction that is to be decoded
and executed.
