Registers in Computer Architecture and Their Role

Computer architecture and
performance

Registers and role in architecture
• Following are the some of the registers that are used in the
computers
• Program Counter - This register is helpful in storing the address of
the next instruction that will be executed by the processor.
• Current Instruction Register – This register holds current
instruction being executed.
• Memory Address Register - It stores RAM address to which next
read or write operation is to be done.
• Memory Data Register : The register holds the data which is read
from RAM or is to be written to RAM.

Registers and Processors
• Accumulators - These type of Registers holds data on which any
process will work on as well as the results of logical or arithmetical
operations.
• Status Register - It holds information about last carried out
operation by the processor such as whether last sum operation
produced a positive or negative result.
• Interrupt Register - This register is responsible for holding the
information about any kind of interrupt that may happen at the time
of processing.

Processing cycle
• FETCH
• CPU reads contents from PC(Program Counter) in order to get the
address of next process instruction which needs to be executed.
After it is fetched, decoded. For instance it is 3264.
• As soon as the address if the next instruction is read value of the
PC increases and becomes PC = PC + 1(3265)
• Contents of 3264 are loaded on MAR.
• Addresses in MAR register is then placed in RAM.